The International Regulations for Preventing Collisions at Sea

 

With notes by Lee Taylor

 

CONTENTS

 

PART A         GENERAL

 

RULE 1         APPLICATION

RULE 2         RESPONSIBILITY

RULE 3         GENERAL DEFINITIONS

 

PART B         STEERING AND SAILING RULES

 

SECTION I       CONDUCT OF VESSELS IN ANY CONDITION OF VISIBILITY

 

RULE 4         APPLICATION

RULE 5         LOOK-OUT

RULE 6         SAFE SPEED

RULE 7         RISK OF COLLISION

RULE 8         ACTION TO AVOID COLLISION

RULE 9         NARROW CHANNELS

RULE 10        TRAFFIC SEPARATION SCHEMES

 

SECTION II      CONDUCT OF VESSELS IN SIGHT OF ONE ANOTHER

 

RULE 11        APPLICATION

RULE 12        SAILING VESSELS

RULE 13        OVERTAKING

RULE 14        HEAD-ON SITUATION

RULE 15        CROSSING SITUATION

RULE 16        ACTION BY GIVE-WAY VESSEL

RULE 17        ACTION BY STAND-ON VESSEL

RULE 18        RESPONSIBILITIES BETWEEN VESSELS

 

SECTION III

 

RULE 19        CONDUCT OF VESSELS IN RESTRICTED VISIBILITY

 

PART C          LIGHTS AND SHAPES

 

RULE 20        APPLICATION

RULE 21        DEFINITIONS

RULE 22        VISIBILITY OF LIGHTS

RULE 23        POWER-DRIVEN VESSELS UNDERWAY

RULE 24        TOWING AND PUSHING

RULE 25        SAILING VESSELS UNDERWAY AND VESSELS UNDER OARS

RULE 26        FISHING VESSELS

RULE 27        VESSELS NOT UNDER COMMAND OR RESTRICTED IN THEIR ABILITY TO MANOEUVRE

RULE 28        VESSELS CONSTRAINED BY THEIR DRAUGHT

RULE 29        PILOT VESSELS

RULE 30        ANCHORED VESSELS AND VESSELS AGROUND

RULE 31        SEAPLANES AND WIG CRAFT

 

PART D         SOUND AND LIGHT SIGNALS

 

RULE 32        DEFINITIONS

RULE 33        EQUIPMENT FOR SOUND SIGNALS

RULE 34        MANOEUVRING AND WARNING SIGNALS

RULE 35        SOUND SIGNALS IN RESTRICTED VISIBILITY

RULE 36        SIGNALS TO ATTRACT ATTENTION

RULE 37        DISTRESS SIGNALS

 

PART E         EXEMPTIONS

 

RULE 38        EXEMPTIONS

 

ANNEX I        POSITIONING AND TECHNICAL DETAILS OF LIGHTS AND SHAPES

 

ANNEX II        ADDITIONAL SIGNALS FOR VESSELS FISHING IN CLOSE PROXIMITY

 

ANNEX III       TECHNICAL DETAILS OF SOUND SIGNAL APPLIANCES

 

ANNEX IV       DISTRESS SIGNALS

 

 

 

PART A – GENERAL

 

Rule 1

 

Application

 

(a)       These Rules shall apply to all vessels upon the high seas and in all waters connected therewith navigable by seagoing vessels.

 

This means if it is a boat or ship that can be controlled by a human being and can go away to sea and come back again, the Rules apply to it, so long as the body of water in which it currently rests is accessible by water from the sea. This means it does not apply to reservoirs or lakes, for example, where amateur yachting might go on, or castle moats, or fishing lakes in which people might use boats. It does apply to canals, rivers (up to the point where it is too shallow) and other places not accessible to even fairly small merchant ships.

 

(b)       Nothing in these Rules shall interfere with the operation of special rules made by an appropriate authority for roadsteads, harbours, rivers, lakes or inland waterways connected with the high seas and navigable by seagoing vessels. Such special rules shall conform as closely as possible to these Rules.

 

In other words, special rules made for the aforementioned areas (accessible by and navigable by seagoing vessels) by the authorities that govern them trump the IRPCS rules. However, where such rules exist, they can be expected to resemble these Rules. It is therefore crucial that when proceeding along such areas, the navigator researches whether such rules exist.

 

(c)        Nothing in these Rules shall interfere with the operation of special rules made by the Government of any State with respect to additional station or signal lights, shapes or whistle signals for ships of war and vessels proceeding under convoy, or with respect to additional station of signal lights or shapes for fishing vessels engaged in fishing as a fleet. These additional station or signal lights, shapes or whistle signals shall, so far as possible, be such that they cannot be mistaken for any light, shape or signal authorised elsewhere under these Rules.

 

This part is similar to part (b), except that it applies to shapes, lights and whistle signals, and stipulates that instead of making such signals resemble existing signals, they should be sufficiently different so as to be impossible to confuse with existing signals. In short, then it is the opposite of (b), and applies to signals.

 

This rule should be compared with Rule 36, which describes how signals to attract attention should be impossible to confuse with signals described elsewhere in the Rules.

 

(d)       Traffic separation schemes may be adopted by the Organisation for the purpose of these Rules.

 

Any traffic separation scheme that is not adopted by the International Maritime Organisation does not need to be navigated in the manner described in these Rules. However, if such a scheme exists that isn’t adopted by the IMO, the rules describing how to navigate through it consist of ‘special rules’ made by the government of the appropriate state, and those Rules should resemble the existing Rules as closely as possible.

 

(e)       Whenever the Government concerned shall have determined that a vessel of Special construction or purpose cannot comply fully with the provisions of any of these Rules with respect to the number, position, range or arc of visibility of lights or shapes, as well as to the disposition and characteristics of sound-signalling appliances, such vessel shall comply with such other provisions in regard to the number, position, range or arc of visibility of lights or shapes, as well as to the disposition and characteristics of sound-signalling appliances, as her Government shall have determined to be the closest possible compliances with these Rules in respect of that vessel.

 

Certain vessels (the most common given example is the aircraft carrier) are oddly shaped, usually because their purpose and function demands it. A vessel of this design must show signals that most closely resemble the signals that a vessel is required to show according to the Rules. This is said in a particularly long-winded way, but it is quite important; it means that the spacing and arrangement of lights might sometimes deviate from what is expected.

There is a specific exemption for the need to comply with the positioning of lights and shapes for WIG craft and seaplanes under Rule 31. This differs from this Rule, in that it only applies to lights and shapes, and no government sanction is required.

 

Rule 2

 

Responsibility

 

(a)       Nothing in these Rules shall exonerate any vessel, or the owner, master or crew thereof, from the consequences of any neglect to comply with these Rules or of from the neglect of any precaution which may be required by the ordinary practice of seamen, or by the special circumstances of the case.

 

There are many examples where an incident at sea might be avoided by common sense or by ‘the common practice of seamen’. As not every example of what this might be entail can be described in the Rules, this part serves as a ‘catch all’, which means that if the vessel in which you are in control of has a collision, even if you were in compliance with all the rest of the Rules, if you have not acted in accordance with the ordinary practice of seamen (or taking into account the ‘special circumstances of the case’), and this was actually relevant, then you would be considered responsible.

 

Since failure to comply with such ordinary practices is considered, according to this part, to be in contravention of the Rules, such practises can be considered to be a part of the Rules, and must be complied with, even though they are not stated within the Rules.

 

This part can be considered to include a combination of experience at sea, situational awareness, and guidance described elsewhere, such as in the international chamber of shipping bridge procedures guide, or in marine guidance notices.

 

It can also be interpreted to mean that if you have a collision, that you are considered responsible even if you complied with the Rules to the letter (which should, in theory never happen). Under this (cynical) interpretation, if you have a collision, it’s because you have failed to act with the ordinary practice of seamen.

 

(b)       In construing and complying with these Rules due regard shall be had to all dangers of navigation and collision and to any special circumstances, including the limitations of the vessels involved, which may make a departure from these Rules necessary to avoid immediate danger.

 

This means, in a nutshell, that if it is necessary to make a departure from the Rules, that you should make the departure, and if you do not, the results of failing to make that departure are yours. Such departures might include alterations of course for navigational purposes, not the purpose of collision avoidance.

 

It can also be interpreted to mean that if you have a collision, that you are considered responsible even if you complied with the Rules to the letter (which should, in theory never happen). Under this (cynical) interpretation, if you have a collision, it’s because you have failed to make a departure from the Rules when necessary.

 

Rule 3

 

General Definitions

 

For the purpose of these Rules, except where the context otherwise requires:

 

(a)       The word ‘vessel’ includes every description of watercraft, including non-displacement craft, WIG craft and seaplanes, used or capable of being used as a means of transportation on water.

 

This part should be read with reference to Rule 1(a), which states that the rules apply to vessels upon the high seas and upon any body of water which is connected to the high seas. Therefore, this rule doesn’t apply to vessels which aren’t actually in the water, hence a seaplane, whilst flying, isn’t a vessel.

The rules also make reference to ‘objects’, for example, in the towing rules of Rule 24. Objects are not vessels, although they are in the water, because they are not ‘craft’ because they are not capable of being used as a means of transportation over water. This distinction is important; buoys, dracones, and other objects upon which human beings cannot tread are never vessels, although if people can ride on it, it can be considered a vessel.

A barge that has no means of self-propulsion can be ridden and so counts as a vessel.

 

(b)       The term power driven vessel means any vessel propelled by machinery.

 

The aforementioned seaplane, when on the water, is propelled by the rotary action of its blades. Although these propel the craft by utilising air, not water, the craft still makes way because it is powered by machinery and thus is still to be considered a power-driven vessel.

A vessel under sail which is also utilising a motor is considered a power-driven vessel, not a sailing vessel, as is mentioned below.

Note that only power-driven vessels can be considered vessels constrained by their draught. Any other type of vessel, for example a vessel at anchor, a fishing vessel, or a vessel not under command, might be any type of vessel, not just a power-driven vessel.

A power-driven vessel is still considered a power-driven vessel even when it not using its engines, that is, when it is stopped and making no way through the water.

 

(c)        The term sailing vessel means any vessel under sail provided that propelling machinery, if fitted, is not being used.

 

As mentioned above, a sailing vessel when using propelling machinery is considered a power-driven vessel.

A vessel that has both the capacity to propel itself by sail or machinery is considered a sailing vessel when it uses neither method of propulsion, so sail trumps machine if stopped and making no way, but if both are being used, and the vessel is making way under power, then it is considered a power-driven vessel.

 

(d)       The term vessel engaged in fishing means any vessel fishing with nets, lines, trawls or other fishing apparatus which restrict manoeuvrability, but does not include a vessel fishing with trolling lines or other fishing apparatus which do not restrict manoeuvrability.

 

As mentioned before, any type of vessel can be considered a vessel engaged in fishing, as long as that is what it is doing. This means it could be a power-driven vessel, a sailing vessel, or even a rowing boat. However, whatever type of vessel it is, it is treated as a fishing vessel and only that for the purposes of lights, shapes and whistle signals if it is fishing in such a way that restricts its manoeuvrability.

Note that even though a fishing vessel is defined as a vessel restricted in its manoeuvrability due to the fact that it is fishing, it is never treated as a vessel restricted in its ability to manoeuvre, only as vessel engaged in fishing. This point comes up in later rules.

 

(e)       The term seaplane includes any aircraft designed to manoeuvre on the water.

 

As mentioned above, the Rules do not apply to aircraft that are not ‘upon the high seas’, and so whether or not an aircraft is a seaplane, it is only treated as a seaplane according to the Rules when it is in the water.

Note also that any type of aircraft is referred to as a seaplane. This means helicopters and airships are also considered ‘seaplanes’ if they are capable of landing on the water.

 

(f)         The term vessel not under command means a vessel through some exceptional circumstance is unable to manoeuvre as required by these Rules and is therefore unable to keep out of the way of another vessel.

 

The operative term here is ‘through some exceptional circumstance’. Thus, the watch cannot have decided to leave the bridge to have a party and throw up the not under command lights; this term is meant to be interpreted as, ‘if something that could not have been foreseen occurs to the ship, or, if it was foreseen, could not have been avoided.’ To reiterate yet again, something needs to break (usually). Because of the exceptional circumstance, the vessel has been rendered ‘unable to manoeuvre’ as required by the Rules, and thus, usually, this must be a result of a steering gear failure, or main propulsion failure (or the oars could have fallen into the water, or the sail has been eaten by giant semi-aquatic moths; the rule does not apply exclusively to power-driven vessels.)

There are other potential incidents which would leave a vessel not under command. If there are no officers to maintain a watch, a vessel literally has no-one to command it, for example, and is thus not under command. This might happen if there is a fire on board, and all hands are fighting the fire. Or, it might be that a watch is being maintained, but a vessel cannot manoeuvre because it must keep the fire on the lee side of the vessel, and thus cannot turn.

This does not mean that a vessel not under command necessarily requires assistance, and it does not mean that a vessel not under command is in distress; this is emphatically illustrated by Rule 27(h).

 

(g)       The term vessel restricted in her ability to manoeuvre means a vessel which from the nature of her work is restricted in her ability to manoeuvre as required by these Rules and is therefore unable to keep out of the way of another vessel. The term vessels restricted in their ability to manoeuvre shall include but not be limited to:

           

The primary difference between a vessel not under command, as far as the Rules go, is made clear here; ‘through the nature of her work’ is the operative term. A vessel which cannot manoeuvre in the manner the rules require because of her work isn’t unable to alter course or speed because of some exceptional circumstance, but because of normal circumstance.

Note that the list that follows is not necessarily an exhaustive list. If a vessel would otherwise be considered a power-driven vessel or sailing vessel and it cannot manoeuvre as required by the Rules, then it can be considered a vessel restricted in her ability to manoeuvre as defined by this Rule, so long as it displays the appropriate shapes and whistle signals.

 

(i)         a vessel engaged in laying, servicing or picking up a navigation mark, submarine cable or pipeline;

 

Such vessels can be identified by a cable protruding from the bow and/or stern of the ship. They are most likely following a cable or pipeline that is described on the chart and will likely provide information regarding their route and activity by radio in the form of a security announcement.

 

            (ii)        a vessel engaged in dredging, surveying or underwater operations;

           

Please note that these types of vessels may present special lights or shapes appropriate only to this group of vessels restricted in their ability to manoeuvre. This is described in Rule 27 part (d).

 

(iii)       a vessel engaged in replenishment or transferring persons, provisions or cargo while underway;

            (iv)       a vessel engaged in mine clearance operations;

 

Such vessels display different lights and shapes to other vessels restricted in their ability to manoeuvre, as described in Rule 27 part (f). Other vessels are directed to keep 1000m away from such a vessel, which is about five and a half cables.

 

            (vi)       a vessel engaged in a towing operation such as severely restricts the towing vessel and her tow in their ability to deviate from their course.

 

It is worth mentioning specifically that vessels engaged in towing or towing alongside are not necessarily restricted in their ability to manoeuvre; they are treated as power-driven vessels unless they show the shapes and lights of a vessel restricted in her ability to manoeuvre.

Vessels pushing other vessels or objects ahead are not towing vessels, but if doing so causes the pushing vessel to be restricted in its ability to manoeuvre, then it can display the appropriate lights, shapes and whistle signals for such a vessel.

 

PART B – STEERING AND SAILING RULES

 

Section I – Conduct of vessels in any condition of visibility

 

Rule 4

Application

 

Rules in this section apply in any condition of visibility.

 

This means both inside and outside areas of restricted visibility, and by day or night.

 

Rule 5

Look-out

 

Every vessel shall at all times maintain a proper look-out by sight and hearing as well as by all available means appropriate in the prevailing circumstances and conditions so as to make a full appraisal of the situation and of the risk of collision.

 

This is considered by most officers of the watch to be one of the most important rules. It is assumed that such a look-out shall normally consist of an officer of the watch plus one watch rating, but that the officer alone may be sufficient during the day time and in good visibility, and in conditions of restricted visibility, high traffic, or other hazardous conditions in which to navigate, there shall be more watch ratings on the bridge and/or the Master.

By ‘all available means’, usually, this means using the radar, and using it properly. Proper use of the radar is described in Rule 6 (b), but also elsewhere in the Rules. It does, of course, include any means appropriate; since the Rules were published, the use of AIS has become common and this can also be a useful tool. The Rules allow for the use of radar, and for the navigation of a vessel without access to radar.

Note that this rule provides an explanation of why a look-out is to be kept; sufficient look-out is kept so that the officer who has the con is able to make a full appraisal of what is going on, and what the risk of collision is at any time, if any. ‘Situational awareness’ is a buzz-word(s) that it is good to remember. Look-out should be sufficient to provide enough information to make informed decisions that prevent collisions.

 

Rule 6

Safe speed

 

Every vessel shall at all times proceed at a safe speed so that she can take proper and effective action to avoid collision and be stopped within a distance appropriate to the prevailing circumstances and conditions.

 

This is also considered to be one of the most important Rules. It defines the speed at which a vessel must be travelling *at all times*. In most cases, this is dependent entirely on the vessel’s manoeuvring characteristics, as explained later in this Rule. There are some cases, such as in severe restricted visibility, when one can deduce logically from the Rules certain maximum speeds.

The officer on watch must always be able to alter the vessel’s speed in response to the situation. If this is not possible, then the vessel is not under command and must display the appropriate lights, shapes, and sound signals.

This Rule should be considered alongside Rule 5, since hazardous conditions of navigation not only necessitate lower speeds, but also a greater presence of look-outs. However, a vessel proceeding at a low speed may require fewer look-outs; for example, a vessel proceeding at 4 knots when visibility is 4 miles might require only one look-out in addition to the officer on watch, whereas a vessel proceeding at 12 knots in the same conditions would definitely require at least 2 watch ratings in addition to the officer.

 

In determining a safe speed the following factors shall be among those taken into account:

 

(a)       By all vessels:

            (i)         the state of visibility;

 

As has been mentioned, in reduced visibility, a vessel should travel at a slower speed, as described in Rule 19 (b). A vessel isn’t expected to stop when the visibility is zero; but it is expected to navigate very slowly, and may be expected to reduce speed to the minimum at which she can be kept on course.

 

            (ii)        the traffic density including concentrations of fishing vessels or any other vessels;

 

The assumption is that such vessels are likely to move unpredictably, and because they are in great number, may move into your path often. Travelling at a lower speed allows more time to appraise the situation and thus make the correct decisions when altering course to avoid fishing vessels.

Vessels travelling at a lower speed relative to one another generally have less need to avoid each other by as wide a margin, such that at speed of less than ten knots, only a few cables might need to separate two vessels at the closest point of approach. At lower speeds, it is safe to avoid fishing vessels by a smaller distance, which may be the only way to avoid such vessels.

 

            (iii)       the manoeuvrability of the vessel with special reference to stopping distance and turning ability in the prevailing conditions;

 

This part of this rule means that vessels need to be able to stop quickly enough to avoid a collision, and/or turn quickly enough to avoid a collision. Small vessels can turn on a dime, but large vessels and particular heavy tankers have very long stopping distances and therefore need to travel at a slower speed, IF they need to to avoid a collision.

Since the ability of a vessel to turn is based on how fast the water is flowing over the rudder, a vessel travelling at a slower speed doesn’t necessarily have a tighter turning circle, but by travelling at a slower speed, an officer can allow his or her self more time to appraise the situation before making a decision in which the ability of the vessel to make turns is a factor.

The ability of the vessel to reduce its speed, and make a turn, may be influenced by other factors, including the sea state and other meteorological conditions, the physical condition of the vessel (these rules apply to ALL vessels, including vessels that are not under command or restricted in their ability to manoeuvre), draught, trim, current, and so forth. This is what is meant by ‘prevailing conditions.’

 

            (iv)       at night the presence of background lights such as from shore lights or from backscatter of her own lights;

 

The distinction between the navigational lights of other vessels and the lights of vehicles and buildings ashore is sometimes finer than the seaman would like. Vessels may approach from the land, and so may not become apparent on radar or visually in sufficient time for them to be detected and avoided. Proceeding at a slower speed allows the officer on watch to allow more time for appraisal of the situation, allowing the officer to detect vessels that might otherwise be confused with shore lights.

 

            (v)        the state of wind, sea and current, and the proximity of navigational hazards;

 

A vessel should travel under sufficient power to keep its course given the available conditions of wind and current. Especially where there are navigational hazards nearby, such as shallows and rocks, this may limit the options of the navigator, and necessitate being not under command or constrained by draught.

Sometimes, because of such conditions, a ‘safe speed’ may be the highest the vessel is capable of.

Where there is a great deal of current and/or leeway, the vessel’s heading and her course made good may be quite different. This will be exacerbated by steaming slowly through the water, but it may also be prudent to do so, if navigation becomes difficult because of these factors.

 

            (vi)       the draught in relation to the available depth of water.

 

Vessels may sometimes be constrained by their draught. Generally, moving at a slower speed is recommended in such situations, especially when travelling along narrow channels, such as a canal. This makes it easier to alter course around tight corners.

Squat can have a significant impact on safety of navigation. Where there is little depth of water relative to draught, a high speed can cause the keel to touch bottom, causing damage to the keel and/or causing the vessel to run aground. At low speeds, even when there is very little underkeel clearance, squat will be minimised. Thus in these conditions, safe speed will be necessarily low.

 

(b)       Additionally, by vessels with operational radar equipment;

            (i)         the characteristics, efficiency and limitations of the radar equipment;

 

An understanding of the principles of radar and radar displays is important. Understanding that radars do not always produce accurate representations of the locations of objects to be avoided allows the officer on watch to determine whether or not the radar can be trusted, when determining safe speed, and also when determining if a higher speed is safe when otherwise a lower speed would be used, for example, in restricted visibility.

 

            (ii)        any constraints imposed by the radar range scale in use;

           

It is expected that the radar operator will change range scales to optimise their ability to appraise the situation. By engaging in radar scanning, the prudent officer of the watch can obtain early warning of oncoming objects, and by selecting an appropriate range scale, can obtain accurate and relevant information relating to identifying risks of collision at close range that immediately need to be avoided.

Although here, the range scale in use is described as the determining factor in determining safe speed, in fact, it will be the other way around; the range scale shall be adapted to the current speed. A vessel travelling at only 4 knots will not need to set the radar to more than a 6 mile range; a vessel steaming ahead at 25 knots will not want less than a 6 mile range, off-centred to maximise the view ahead, and preferably will use a 12 mile range.

 

(iii)       the effect on radar detection of the sea state, weather and other sources of interference;

 

Especially when navigating by radar alone, but also when visibility is sufficient that the vessel cannot be considered in or near an area of restricted visibility, the reception of radar signals can be obstructed or even obliterated. Within a 12 mile range, large patches may be covered with rainfall or other large particles of precipitation or fog, which may obscure vessels within visually and by radar.

This must be allowed for when considering safe speed. Although areas of restricted visibility should prompt a reduction in speed, if radar is compromised (and there are methods of detecting that this is the case that an experienced operator will know of) the speed should be reduced further, as it becomes dangerous to navigate by radar alone.

 

            (iv)       the possibility that small vessels, ice and other floating objects may not be detected by radar at an adequate range;

 

Ice, wood and fibreglass are poor radar reflectors. It is not sensible to reduce speed in all locations, even knowing that such objects might not be detected if they are present, because yachts, certain fishing boats and icebergs are not likely to be present in most parts of the sea. However, in areas where they might be expected, it is prudent to reduce speed, especially in restricted visibility and at night.

Vessels of less than 12 metres in length sport masthead lights that are only required to have nominal ranges of 2 miles, and such vessels have much shorter nominal ranges for sound signalling appliances. Small objects of wooden or fibreglass construction are not likely to appear on radar either, so even outside of restricted visibility, extra look-outs may be required, and it is prudent to reduce the speed.

 

            (v)        the number, location and movement of vessels detected by radar;

           

Generally speaking, when traffic density is high, a safe speed will be lower. However, using a radar (especially with an ARPA, but otherwise, using radar plotting) it is possible to identify the exact movements of a large group of vessels, and thus determine whether or not risk of collision exists more accurately. With such an ability, less time may be needed to appraise the situation, so a higher speed is justified.

 

(vi)       the more exact assessment of visibility that may be possible when radar is used to determine the range of vessels or other objects in the vicinity.

 

It is sometimes difficult to judge the distance of objects observed visually. Atmospheric conditions can lead to abnormal refraction, and knowing that this is the case, the wise officer of the watch will determine that a safe speed is lower. However, whilst abnormal refraction can affect the effective range of radars, it does not alter the distance at which radar targets are identified. Therefore, in such conditions, there may be no need to reduce speed, since the problems caused by such atmospheric conditions are nullified by the use of radar.

 

Rule 7

 

Risk of Collision

 

(a)       Every vessel shall use all available means appropriate to the prevailing circumstances and conditions to determine if risk of collision exists. If there is any doubt such risk shall be deemed to exist.

 

This is clearly an important rule. It means that, in addition to keeping a proper look-out by sight and hearing and by radar, the officer on watch shall also keep watch by whatever other methods are appropriate given the current situation. This includes using the AIS and any other appropriate equipment available on the bridge. It also means that if necessary, look-outs should be put up forward, for example, in severely restricted visibility, since this is considered an appropriate means to detect risk of collision in that particular circumstance.

That should doubt exist assumption that there is a risk of collision should be made is also very significant; for example, the Rules require (Rule 19 part (e)) that if a sound signal is heard forward of the beam in restricted visibility, a vessel shall reduce her speed to the minimum she can be kept on course. According to this rule, if it is not certain that a sound signal has been heard abaft the beam in restricted visibility, doubt exists and therefore it shall be assumed that a risk of collision exists, in which case appropriate action should be taken (which in this case would mean reducing speed).

Note that if doubt exists as to whether or not there is a risk of collision, collision avoidance cannot be undertaken if the location of the source of the risk of collision cannot be determined.

This part should mainly be construed as to mean that where it is impossible to be reasonably certain that a risk of collision does not exist, that a risk of collision does; therefore, it is better to err on the side of caution.

 

(b)       Proper use shall be made of radar equipment if fitted and operational, including long-range scanning to obtain early warning of risk of collision and radar plotting or equivalent systematic observation of detected objects.

 

The importance of long-range scanning was described in the notes for Rule 6 (b), but it should be noted here that the Rules specifically require the radar to be used if it is present, and for it to be used correctly.

Most people do not engage in radar plotting with a sheet of paper any more. The equivalent systematic observation described most should be read as ‘ARPA’. ARPA should be used if available, and if not, then radar plotting should be.

 

(c)        Assumptions shall not be made on the basis of scanty information, especially scanty radar information.

 

This is a very general rule, but one that is especially important with regards to interpreting sound signals and radar information. If clutter is significant, for example due to inclement weather, then objects may not be detected by radar at an adequate range, or at all, and if they are, they may be false echoes. Forearmed with the knowledge that this is the case, then as per Rule 6, the vessel’s safe speed should be lower; in such conditions, it is forbidden by the Rules to assume that vessels are not on a collision course, for example. There are other situations in which scanty information could lead to mistakes; this rule requires the seafarer to identify when information is ‘scanty’, which means ‘insufficient to base decisions on’, and to proceed with due caution in the knowledge that it cannot be relied upon.

 

(d)       In determining if risk of collision exists the following considerations shall be among those taken into account:

            (i)         such risk shall be deemed to exist if the compass bearing of an approaching vessel does not appreciably change;

 

This is the ‘iron rule’ of collision avoidance. In conditions outside of restricted visibility, whether or not risk of collision exists shall be determined by taking a series of compass bearings. It should not be necessary to use the radar as the primary means of detecting the presence of other vessels at range. It is irresponsible to act to avoid collision without taking a series of compass bearings beforehand.

When using this method to determine if risk of collision exists, it can be assumed that the other vessel is sufficiently visible to allow the aspect of the other vessel to be determined, which is essential to identify what it is doing and therefore take the appropriate action.

It is important to note that only when another vessel is approaching does a risk of collision need to be assumed to exist when there is no bearing change. Vessels that are at a steady range or that are retreating do not pose a risk of collision.

 

            (ii)        such risk may sometimes exist even when an appreciable bearing change is evident, particularly when approaching a very large vessel or a tow or when approaching a vessel at close range.

 

This short list is by no means definitive. For example, ‘tow’ can also refer to vessels being pushed ahead.

This part of the rule assumes that the bearing is being taken from only one part of the object. So long as there is some part of the object for which no bearing change is evident, risk of collision does exist. In other words, in order to determine if risk of collision exists, take a bearing of both the stern and the bow of such an object, and if between the bearing change of those two parts of an approaching vessel there is some part where the bearing change is zero, risk of collision definitely exists.

 

Rule 8

 

Action to avoid collision

 

It is worth recalling at this stage that this Rule applies in all conditions of visibility, that is, in restricted visibility, as well as out of it.

 

(a)       Any action to avoid collision shall be taken in accordance with the Rules of this Part and shall, if the circumstances of the case admit, be positive, made in ample time and with due regard to the observance of good seamanship.

 

This means that whenever action is taken to avoid collision in accordance with any other Rule, whether in or outside of restricted visibility, such an action shall be undertaken in the manner which is dictated in this rule.

This rule also states that such action shall be bold, taken early, and shall also be acceptable to a good seaman. That is, it should not ignore the sensible precautions that would be undertaken by any competent officer of the watch, which means that it should take into account weather, the current and sea state, the depth of water, knowledge of the likely movements of other vessels and any other considerations that a good officer would normally take into account.

 

(b)       Any alteration of course and/or speed to avoid collision shall, if the circumstances of the case admit, be large enough to be readily apparent to another vessel observing visually or by radar; a succession of small alterations of course and/or speed should be avoided.

 

This reiterates the ‘positive action’ described in the previous part, but expands upon it. This part of the rule requires that action should be readily apparent to another vessel; this means that whilst it is important to take early action, it may also be important to wait until another vessel can be reasonably certain of witnessing that such action has been taken.

Note also that whilst this rule states that making small alterations of course and/or speed should be avoided, if it turns out that that is the most prudent option, then this rule requires that it is that action that is taken. For example, it may be that making a bold alteration of course later will only lead to another close-quarters situation, whereas a small alteration earlier will eradicate that problem. The exact wording can be interpreted as, ‘If possible, alterations of course should be broad, and alterations of speed significant. Making small alterations of course and altering the speed only a little is not something you should do, if it is possible to avoid it.’

This means that even if a bold alteration of course is ultimately more of a hassle, and it would be easier to only make a slight alteration, but the bold alteration is safe to take, then the bold alteration of course should be taken.

 

(c)        If there is sufficient sea-room, alteration of course alone may be the most effective action to avoid a close-quarters situation provided that it is made in good time, is substantial and does not result in another close-quarters situation.

 

This part essentially acknowledges that it is not always necessary to reduce speed, when that is an option, so long as by only altering course, close-quarters situations can be avoided. This is fortunate since shipping companies don’t particularly like their vessels to slow down!

This part of this rule announces that alteration of course alone may be the most effective action. Alteration of speed can be difficult to notice either visually or by radar, and so should not be the first option considered during action taken to avoid a collision. The preference should be alteration of course, except where that is not an option.

 

(d)       Action taken to avoid collision with another vessel shall be such as to result in passing at a safe distance. The effectiveness of the action shall be carefully checked until the other vessel is finally past and clear.

 

Whenever action is taken to avoid a collision, such an action shall always be bold enough to result in passing at a safe distance, in other words, not so close that a sudden change in conditions will necessarily lead to another risk of collision developing. The situation should be monitored until it is certain that there is no longer any risk of collision.

 

(e)       If necessary to avoid collision or allow more time to assess the situation, a vessel shall slacken her speed or take all way off by stopping or reversing her means of propulsion.

 

When it is not possible to avoid collision by alteration of course, an officer is required to reduce speed. However, the officer is also allowed to reduce the speed of the vessel in order to fully appraise the situation. This part goes hand in hand with Rule 6, which concerns safe speed. If a vessel is going so fast that the officer holding the watch cannot determine whether or not there is any immediate risk of collision, then she is not travelling at a safe speed. Because this rule allows for slackening speed, it requires it, if necessary.

Note that outside of restricted visibility, a sound signal accompanies reversing propulsion; three short blasts on the ship’s whistle, as per Rule 34 (a).

 

(f)         (i)         A vessel which, by any of these Rules, is required not to impede the passage or safe passage of another vessel shall, when required by the circumstances of the case, take early action to allow sufficient sea-room for the safe passage of the other vessel.

 

It isn’t made clear what the difference between ‘safe passage’ and ‘passage’ is in the rules. It may be that allowing another vessel safe passage means to navigate in a way that does not put it at risk of collision or forces it to navigate into danger, whilst not impeding the passage of another vessel merely means not forcing it to alter course or speed at all, but not for the purposes of its safety. It may be that this specific phrasing refers to rules 9, 10 and 18, which specifically use the terms passage and safe passage respectively.

There are a handful of instances in which a vessel is literally referred to as being a vessel the safe passage of which other vessels are not to impede, as described in Rule 18 part (d); a vessel constrained by her draught and Rule 9; which refers to vessels that are navigating within a narrow channel or fairway (from the point of view of a fishing vessel, a sailing vessel, or vessel less than 20m in length), and vessels which can only navigate within such a narrow channel or fairway (from the point of view of a vessel which is crossing such a narrow channel or fairway). In addition, under Rule 10 part (i) and (j), vessels less than twenty metres in length and sailing vessels must not impede power-driven vessels in TSSs, and fishing vessels may not impede the passage of any vessels in TSSs. Vessels not under command or restricted in their ability to manoeuvre are exempted from this, and other vessels are only required to avoid impeding the safe passage of vessels constrained by their draught if the circumstances of the case admit.

Rule 18 also lays out the general responsibilities between vessels, in particular which vessels are directed to ‘keep out of the way’ of other vessels. Although it is not specifically stated that ‘keep out of the way’ or ‘keep clear’ means ‘do not impede the passage or safe passage of’, it is generally assumed that these meanings are synonymous, but the difference is significant; a vessel not to be impeded is a vessel which, through your actions, should not be forced to deviate from its planned course.

Under this part of this rule, it is merely stipulated that when taking action to avoid impeding another vessel, such action shall be as early as is practicably possible. This resembles part (a) of this Rule, which requires actions made to avoid collision to be made in ample time. Since action taken to avoid impeding the passage or safe passage of another vessel is not action to avoid collision, this part of this rule is required to pronounce the importance of taking action early.

 

            (ii)        A vessel require not to impede the passage or safe passage of another vessel is not relieved of this obligation if approaching the other vessel so as to involve risk of collision and shall, when taking action, have full regard to the action which may be required by the Rules of this part.

 

This rule exists to ensure that there is no possible conflict between this part (f) and part (a) of this Rule. In other words, a vessel may be required to obey both (a) and (f), not one or the other.

 

            (iii)       A vessel the passage of which is not to be impeded remains fully obliged to comply with the Rules of this part when the two vessels are approaching on another so as to involve risk of collision.

 

This rule definitely requires vessels the passage of which is not to be impeded to follow this rule, in other words, they must not impede each other’s passage or safe passage. This rule refers only to this part, not the whole rule; the implication is that a vessel the passage of which is not to be impeded is a vessel that is constrained by its draught, or otherwise is unable to alter course freely, and thus not able to comply with the other parts of this rule, such complying with such parts requires the vessel to manoeuvre freely.

 

Rule 9

 

Narrow channels

 

It should be recalled that these rules apply in all conditions of visibility, but that some parts of this rule refer to sound signals that are only sounded when two vessels are in sight of one another.

 

(a)       A vessel proceeding along the course of a narrow channel or fairway shall keep as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable.

 

It is fairly easy to remember the way this rule works; it is somewhat analogous to the way a car is driven on the road in most parts of the world, that is, on the right.

The important thing to remember is that a narrow channel or fairway may be a canal of some description, or a much wider body of water with a deep water channel in which one vessel can safely navigate. A ‘narrow channel or fairway’ is only considered as such when a vessel has a draught that forbids it from deviating from her planned passage; in other words, it may be a narrow channel for one vessel whilst not being so for another. This fact exemplifies the importance of Rule 8 (f), which dictates the actions of vessels required not to impede the passage of vessels which are navigating within a narrow channel or fairway. Not all vessels in proximity to one another are necessarily operating in a narrow channel or fairway within the context of this Rule.

 

(b)       A vessel of less than 20m in length or a sailing vessel shall not impede the passage of a vessel which can safely navigate only within a narrow channel or fairway.

 

A vessel which can safely navigate only within a narrow channel or fairway does not necessarily have to show the lights or shape for a vessel constrained by its draught, as dictated in Rule 28, but all vessels including vessels not under command and vessels restricted in their ability to manoeuvre are required to avoid impeding a vessel which can safely navigate only within a narrow channel or fairway, even if it is showing itself to be a vessel constrained by its draught, despite any exemptions described under Rule 18 part (d), so long as such vessels are less than 20m in length, or are sailing vessels.

 

(c)        A vessel engaged in fishing shall not impede the passage of any other vessel navigating within a narrow channel or fairway.

 

Note that vessels engaged in fishing are not merely required to avoid impeding vessels that can safely navigate only within a narrow channel or fairway; they are required to avoid impeding all vessels. This rule is somewhat ambiguous, since a narrow channel for one vessel may be open water for another. However, under Rule 18, both sailing vessels and power-driven vessels (so long as they are not under any special condition) are required to keep clear of a vessel engaged in fishing; this Rule may apply to vessels which are incapable of keeping clear.

There are some narrow channels and fairways which are bounded by land or structures rising above the waterline, for example, canals. Such an area can be considered a narrow channel by all vessels, in which case, a vessel engaged in fishing can avoid impeding any other vessel (including other fishing vessels) in compliance with this Rule.

 

(d)       A vessel shall not cross a narrow channel or fairway if such crossing impedes the passage of a vessel which can safely navigate only within such a channel or fairway. The latter vessel may use the sound signal prescribed in Rule 34(d) if in doubt as to the intention of the crossing vessel.

 

This is the general signal for when a vessel is in doubt as to whether the other vessel is taking sufficient action to avoid a collision, or if a vessel fails to understand the intentions or actions of another. It consists of at least five (but potentially more) short blasts on the ship’s whistle (which can be remembered by the Morse Code ‘5’, ▪ . )

Note that in this case, the vessel proceeding through a narrow channel or fairway is not classed as a vessel the passage of which is not to be impeded by the crossing vessel; the crossing vessel is merely forbidden to cross if such a crossing would impede the passage of the vessel in the narrow channel or fairway. The difference is slight and ultimately it means that the crossing vessel must find another location to cross, or wait for the vessel in the narrow channel or fairway to pass by.

 

(e)       (i)         In a narrow channel or fairway when overtaking can take place only if the vessel to be overtaken has to take action to permit safe passing, the vessel intending to overtake shall indicate her intention  by sounding the appropriate signal prescribed in Rule 34(c)(i). The vessel to be overtaken shall, if in agreement, sound the appropriate signal prescribed in Rule 34(c)(ii) and take steps to permit safe passing. If in doubt she may sound the signals prescribed in Rule 34(d).

 

The vessel intending to overtake another vessel shall make the sound signal as prescribed in Rule 34(c)(i) consisting of two prolonged blasts followed by one short blast if she intends to overtake on the starboard side, and two prolonged blasts followed by two short blasts if she intends to overtake on the port side. This can be remembered as the ‘MIKE’ in the Morse Code (▬ ), followed immediately by either ‘ECHO’ in the Morse Code (▪), or ‘INDIA’ in the Morse Code (▪▪).

The sound signal to be made in agreement, as described in Rule 34(c)(ii), is one prolonged blast followed by one short blast followed by one prolonged blast followed by one short blast on the ship’s whistle. This can be remembered as ‘CHARLIE’ in the Morse Code, which means ‘affirmative’, ▬ ▪ ▬ ▪.

The signal prescribed in Rule 34 (d) is the signal for indicating doubt or a failure to understand the intentions of another vessel, five or more short blasts on the ship’s whistle, which can be remembered as ‘5’ in the Morse Code, or ▪ .

These sound signals are only to be made when one vessel can be observed visually by the other, in other words, outside of conditions of restricted visibility.

If no special action needs to be taken by the vessel to be overtaken in order for the overtaking vessel to safely overtake the other, there need be no sound signals. This rule only applies if the other vessel needs to move out of the way.

Note that the vessel to be overtaken need not be constrained by her draught or otherwise confined to a narrow channel; only the overtaking vessel need be so confined for this rule to apply.

 

 

            (ii)        This Rule does not relieve the overtaking vessel of her obligation under Rule 13.

 

Rule 13 is the Rule which describes overtaking when vessels are in sight of one another. This rule directs the overtaking vessel to keep out of the way of the vessel being overtaken, shall not become a crossing vessel as described in Rule 15, and defines an overtaking vessel as a vessel coming up with another vessel from a direction more than 22.5° abaft the beam of the vessel being overtaken. It also states that if there is any doubt as to whether a vessel is being overtaken, then it shall be assumed that she is and so the overtaking vessel is directed to act accordingly.

Note, however, that Rule 9 applies in all conditions of visibility, whereas Rule 13 only applies outside of conditions of restricted visibility.

 

(f)         A vessel nearing a bend or an area of a narrow channel or fairway where other vessels may be obscured by an intervening obstruction shall navigate with particular alertness and caution and shall sound the appropriate signal prescribed in Rule 34(e).

 

The sound signal described in Rule 34(e) is one prolonged blast on the ship’s whistle, which can be remember as ‘TANGO’ in the Morse Code, ▬. The response to hearing this sound signal is to reply with one prolonged blast.

Because both vessels are required to make the same signal when approaching such an obscured bend, the vessel which makes this signal first can be regarded as the vessel which will pass through first; this means that the second vessel, knowing that another vessel will soon appear before her bow, ought to reduce her speed so as to allow the vessel making this signal to pass ahead safely. This is not a directive under these Rules, but rather common sense (although common sense comes under the auspices of good seamanship and/or the common practice of seamen, and therefore is required by the Rules.)

 

(g)       Any vessel shall, if the circumstances of the case admit, avoid anchoring in a narrow channel.

 

This is a simple enough Rule to comprehend. This rule clearly exempts vessels that need to anchor in an emergency. This Rule does not forbid vessels from running themselves aground, but such a practice is usually frowned upon by the shipping company!

 

Rule 10

 

Traffic separation schemes

 

(a)       This Rule applies to traffic separation schemes adopted by the Organisation and does not relieve any vessel under her obligation under any other rule.

 

This rule only applies to TSSs adopted by the IMO. Similar unadopted schemes are not obliged to follow this Rule, but since such a scheme would constitute a ‘special rule’ made by an appropriate authority and/or government of any state, vessels are obliged to follow those Rules under Rule 1. Such special rules would resemble these Rules, again in accordance with Rule 1.

This Rule is to be obeyed in all conditions of visibility, and all other Rules must be obeyed in addition to this rule. Note that for collision avoidance purposes, quite different Rules apply inside and outside of restricted visibility.

 

(b)       A vessel using a traffic separation scheme shall:

            (i)         proceed in the appropriate traffic lane in the general direction of traffic flow for that lane;

 

Vessels within TSS lanes often fan out or draw closer together when a lane widens or narrows. Thus, the ‘general direction of flow’ may not follow parallel lines along a lane. This part of this rule means that vessels should follow broadly similar courses, not headings, as they proceed through the lane, appropriate to the shape of the lane and the position in which the vessels are located.

 

            (ii)        so far as practicable keep clear of a traffic separation line or separation zone;

 

There are some exemptions to this part of this rule, described elsewhere in this rule, particularly (e), but also (c), although it is not explicitly stated in (c) that separation lines and zones will be crossed.

 

            (iii)       normally join or leave a traffic lane at the termination of the lane, but when joining or leaving from either side shall do so at as small an angle to the general direction of traffic flow as practicable.

 

It is not explicitly stated in this rule that a vessel shall enter or leave a TSS lane on an angle that is close to the general direction of traffic flow, but this will be necessary if the vessel is to proceed along the entire lane in such a manner.

This rule can be thought of as ‘contradicting’ part (c), and it is quite different. Vessels using the lane must leave, if leaving at either side instead of at either end, at as small an angle to the general direction of flow as possible, but vessels merely crossing the lane must do so with a heading at right angles to the general direction of traffic flow.

Vessels are, as stated here, normally not allowed to leave the lane at the sides, but are allowed to do so as parts (d) and (e) dictate; that is, to avoid immediate danger, or when en-route to or from a destination, or when to engage in fishing within a traffic separation zone, or if they are allowed to use the inshore traffic zone.

 

(c)        A vessel shall, so far as practicable, avoid crossing traffic lanes but if obliged to do so shall cross on a heading as nearly as practicable at right angles to the general direction of traffic flow.

 

It is essential to note that this part of this rule requires the crossing vessel to cross on a heading that is at right angles to the general direction of traffic flow, not her course made good. This is because a strong current may be acting against the direction in which the vessel’s passage is plotted; if she were to make good a course at right angles to the general direction of flow, her speed vector in that direction would be less than if she were to head at right angles across the traffic lane.

The quickest way to cross the traffic lane is to head at right angles across the general direction of flow. This minimises the amount of time spent in the lane, and thus reduces the risk of collision.

Note that in conditions outside of restricted visibility, it is very likely that Rules 15, 16 and 17 will apply, and must still be complied with, as do all Rules. Although this part of this rule stipulates that the vessel must maintain a certain heading, she is exempted from complying with this Rule so far as is necessary to comply with all others, especially in order to avoid a collision.

 

(d)       (i)         A vessel shall not use an inshore traffic zone when she can safely use the appropriate traffic lane within the adjacent traffic separation scheme. However, vessels of less than 20m in length, sailing vessels and vessels engaged in fishing may use the inshore traffic zone.

 

Because these types of vessels are allowed to use the inshore traffic zone, they may cross from a traffic lane across a traffic separation zone or line and thus follow the rules in part (b) and (c), but should avoid using or crossing the lane if possible.

This rule states that vessel engaged in fishing, sailing vessels, and vessels less than 20m in length may use the inshore traffic zone, however, fishing boats that are not yet engaged in fishing are treated as sailing vessels or power-driven vessels of their size, and so would be forbidden to enter the inshore traffic zone if not driven by sail or more than 20m, were it not for the fact that part (ii) of this part states that vessels en-route to or from a location in the zone may enter it. In this case, a fishing boat would be en-route to a location in which she intended to fish.

 

            (ii)        Notwithstanding subparagraph (d)(i), a vessel may use an inshore traffic zone when en route to or from a port, offshore installation or structure, pilot station or any other place situated within the inshore traffic zone, or to avoid immediate danger.

 

Such vessels making use of this exemption are most likely following the rules described in parts (b) and (c).

 

(e)       A vessel other than a crossing vessel or a vessel leaving a lane shall not normally enter a separation zone or cross a separation line except:

            (i)         in cases of emergency to avoid immediate danger;

            (ii)        to engage in fishing within a separation zone.

 

Although crossing vessels and vessels leaving a lane are exempted from the general list of vessels that are forbidden to enter a separation zone or cross a separation line, vessels that are enter a separation zone to avoid danger or engage in fishing can only do so by either crossing a lane or travelling along it for some distance. Therefore it is prudent for such vessels to cross the lane at a heading at right angles to the general direction of traffic flow, or to cross the separation lines at a small to the general direction of traffic flow.

Rules (i) and (j) may apply here; sailing vessels, vessels engaged in fishing and vessels less than 20m in length may navigate across the lanes in such a way as to avoid impeding the passage of vessels using the TSS, but not all vessels that need to enter a separation zone by crossing or travelling through the lanes are allowed to navigate in such a way. A vessel not engaged in fishing, but en-route to a location in a traffic separation zone where it will engage in fishing, propelled by machinery but more than 20m in length, approaching from an in-shore traffic zone, is not required by these rules to avoid impeding the passage of vessels travelling along the lanes of the TSS. She is therefore required to obey part (c) of this Rule and any other rules, and cannot use an obligation not to impede the passage of other vessels to ‘dodge’ her requirements to obey, for example Rule 17, which requires her to stand-on in a crossing situation. This fact is exemplified by part (a) of this Rule as well.

 

(f)         A vessel navigating in areas near the terminations of traffic separation schemes shall do so with particular caution.

 

Vessels entering or leaving a lane will do so at the same angle they were following when travelling in the general direction of flow for that lane. They then are likely to alter course, so as to head to their next waypoint. A vessel making an alteration of course for navigational purposes is not obliged to follow rules that exist to avoid collisions; for example, Rule 17 might require a vessel to hold its course and speed in a crossing situation, but a vessel intending to alter course to keep on its intended track before a collision might occur, hence there is no risk of collision. Vessels near the terminations of TSS lanes must be cautious of precisely this activity; it is best to avoid the area if at all possible.

 

Section II – Conduct of vessels in sight of one another

 

Rule 11

 

Application

 

Rules in this section apply to vessels in sight of one another.

 

Rule 12

 

Sailing vessels

 

Note; author does not understand sailing vessels

 

(a)       When two sailing vessels are approaching one another, so as to involve risk of collision, one of them shall keep out of the way of the other as follows:

           

Although these rules apply only between sailing vessels, it is necessary for officers on board other vessels to understand the manoeuvres of sailing vessel in order to avoid collisions.

Note that in restricted visibility, there are no specific rules governing sailing vessels; all vessels are bound to obey Rule 19 when avoiding collisions.

 

(i)         when each has the wind on a different side, the vessel which has the wind on her port side shall keep out of the way of the other;

 

When two sailing vessels have the wind on different sides, the vessel that has the wind on the port side can make an alteration of course to starboard to avoid a collision, whilst still keeping her sails full. She is, however, merely directed to keep out of the way of the other vessel, so she may make an alteration of course to port.

Her alteration of course may mean that she has the wind on a different side; however, after having made such an alteration, there should no longer be any risk of collision.

 

            (ii)        when both have the wind on the same side, the vessel which is to windward shall keep out of the way of the vessel which is to leeward;

 

If two sailing vessels are approaching one another with the wind on the same side, the vessel to leeward will be fighting against the wind. The vessel to windward will not be fighting the wind, and so is better able to use the wind to power her alteration of course. She is therefore directed to take action to keep clear of the other vessel.

 

            (iii)       if a vessel with the wind on the port side sees a vessel to windward and cannot determine with certainty whether the other vessel has the wind on the port or on starboard side, she shall keep out of the way of the other.

 

If two vessels have the wind on the same side, then the one to windward keeps out of the way of the other. If you have the wind on your port side, then you must keep clear of the other. If you have the wind on your port side but see another vessel to windward, you would not alter course to keep clear unless she also had the wind on her starboard side; this rule means that, if doubt exists, you are directed to keep clear.

It may be that both vessels have the wind on their starboard side, but cannot see if the other vessel has the wind on their starboard side. In this situation, neither vessel can identify whether or not both vessels have the wind on the same or different sides by observing her mainsail. Under strict interpretation of the Rules, this means that neither vessel should make an alteration of course and/or speed to avoid a collision. However, one vessel will know if she is to windward or leeward; the vessel to windward ought to make an alteration of course and/or speed to keep clear, as she ought to be able to judge by the aspect and wind direction whether or not the other vessel has the wind on the port or starboard side.

 

(b)       For the purpose of this Rule the windward side shall be deemed to be the side opposite to that on which the mainsail is carried or, in the case of a square-rigged vessel, the side opposite to that which the largest for-and-aft sail is carried.

 

Rule 13

 

Overtaking

 

(a)       Notwithstanding anything contained in the Rules of part B, sections I and II, any vessel overtaking any other shall keep out of the way of the vessel being overtaken.

 

This part of this rule means that despite what directives may exist that command a vessel to take avoiding action elsewhere in part B, which cover the steering and sailing rules (including those made after this Rule), a any vessel overtaking any other vessel is directed to keep out of the way (keep clear) of the vessel being overtaken.

This is an important rule, because without this Rule, Rule 14, 15, 16 and 17 would take precedence, possibly unnecessarily forcing the overtaking vessel to inconvenience the overtaken vessel or hold her course and speed in a dangerous manner.

Note that this rule applies only when one vessel can be sighted from another. In restricted visibility, Rule 19 applies. Rule 19, part (e), makes a special consideration for, ‘where it has been determined that a risk of collision does not exist, every vessel which hears apparently forward of her beam the fog signal of another… shall reduce her speed to the minimum at which she can be kept on her course.’ An example of such a situation is where one vessel is about to overtake another.

Rule 19 (d) (i) also makes an exception for a situation in which one vessel is overtaking another; in this instance, it is acceptable to alter to port for a vessel forward of the beam, so long as that vessel is being overtaken.

It is worth remembering that an ‘overtaking situation’ only exists in the rules when vessels can visually observe one another. One vessel might overtake another in restricted visibility, but Rule 13 is not to be obeyed.

This rule applies to sailing vessels, overruling the actions required of sailing vessels in Rule 12.

This Rule also applies when Rule 9 part (e) applies, which is when one vessel is approaching another so as to overtake in a narrow channel or fairway, for which Rule 34 part (c) also applies.

 

(b)       A vessel shall be deemed to be overtaking when coming up with another vessel from a direction more than 22.5° abaft her beam, that is, in such a position with reference to the vessel she is overtaking, that at night she would be able to see only the sternlight of that vessel but neither of her sidelights.

 

(c)        When a vessel is in any doubt as to whether she is overtaking another, she shall assume that this is the case and act accordingly.

 

During the day, it may be difficult to determine the relative aspect of another vessel. A crossing situation may resemble an overtaking situation. If there is any doubt, she shall assume that she is overtaking.

She may not be able to tell whether or not she is moving faster than the vessel to be overtaken, but she can only be considered an overtaking vessel when she is; if there is any doubt, she shall, under this rule, assume that she is.

It is conceivable that, under this Rule, a vessel may act as an overtaking vessel when she might actually be a stand-on vessel or a give-way vessel as described by rules 16 and 17. In this case, by acting as an overtaking vessel, the vessel intending to be overtaken may be confused by the actions of the overtaking vessel. For this reason, according with Rule 8, such action should be made earlier rather than later. A vessel confused by the actions of the other may make the sound and perhaps light signal described in Rule 34, that is, five or more short blasts on the ship’s whistle, and perhaps in addition, five or more flashes with a light signalling appliance.

 

(d)       Any subsequent alteration of the bearing between the two vessels shall not make the overtaking vessel a crossing vessel within the meaning of these Rules or relieve her of the duty of keeping clear of the overtaken vessel until she is finally past and clear.

 

By crossing vessel, this part of this Rule refers to Rule 15. It may be that due to part (c) of this Rule, a crossing vessel may act as an overtaking vessel, but if she does, she shall ensure that there is no risk of collision after her action, in accordance with this part of this Rule.

She may not becomes a crossing vessel after overtaking another vessel, but this does not mean that she shall be forbidden from passing ahead of another vessel if she is sufficiently ahead of her that there is no risk of collision. A crossing situation only exists when two vessels are approaching one another in such a way as for there to be a risk of a close-quarters situation developing, so long as such a situation cannot be considered a head-on situation or an overtaking situation.

 

Rule 14

 

Head-on situation

 

(a)       When two power-driven vessels are meeting on reciprocal or nearly reciprocal course so as to involve risk of collision each shall alter her course to starboard so that each shall pass on the port side of the other.

 

This is often known as passing ‘port to port’ or ‘red to red’. This part of this rule only applies to power-driven vessels. It also only applies when two vessels are in sight of each other. Often, power-driven vessels are considered other types of vessel according to the Rules. Where special avoiding action is necessary in the case of such vessels, as described in Rule 18, which governs the responsibilities between vessels, his Rule shall be ignored.

Most of the time, when directed to keep clear of another vessel, especially when two vessels are meeting in a reciprocal manner such as this, the convention to alter course to starboard is maintained. This is for two main reasons; firstly, in order to keep the starboard side free to make this very manoeuvre, and secondly, because the other vessel will most likely expect this very behaviour.

 

(b)       Such a situation shall be deemed to exist when a vessel sees the other ahead or nearly ahead and by night she could see the masthead lights of the other in a line or nearly in a line and/or both sidelights and by day she observes the corresponding aspect of the other vessel.

 

In practice, this will seldom happen. Although it is quite common for head-on situations to occur, as different vessels share shipping lanes, for two vessels to approach one another so as to present to each other both their sidelights is rare.

Additionally, currents may force a vessel’s heading to vary significantly from her course. Observing by sea-stabilised radar alone, an officer on watch might note a head-on situation developing although if observing visually by these terms, she would not necessarily note it.

For these reasons, it is worth noting that a head-on situation is deemed to exist under the circumstances described, but this does not preclude the possibility that such a situation may exist despite these circumstances not being observed. The sole criterion should be that, as described in part (a), both vessels are meeting on reciprocal or nearly reciprocal courses. What this is exactly is open to interpretation, but it differentiates a head-on situation from a crossing situation.

In a crossing situation, the give-way vessel should normally alter to starboard,  and when taking emergency avoiding action, the stand-on vessel should avoid making an alteration of course to port, in accordance with the requirements of Rules 16 and 17. This means that it is not dangerous to take action as if in a head-on situation, so long as it appears that vessels are in a head-on situation, even if they might more properly be considered to be in a crossing situation.

 

(c)        When a vessel is in any doubt as to whether such a situation exists she shall assume that it does exist an act accordingly.

 

As mentioned in the notes for part (b) of this Rule, doubt may exist as to whether or not a head-on situation is developing, but the alternative is for a crossing situation to exist. This part of this rule requires an officer in doubt to err on the side of ‘head-on’, which in any case will lead to a safe course of action that prevents collision.

 

Rule 15

 

Crossing situation

 

When two power-driven vessels are crossing so as to involve risk of collision, the vessel which as the other on her own starboard side shall keep out of the way and shall, if the circumstances of the case admit, avoid crossing ahead of the other vessel.

 

This rule is the first of three rules, 15, 16 and 17, that govern actions in a crossing situation. The crossing situation can be considered the ‘default’ risk-of-collision situation, except for when, as the Rules described, the situation in which there is a risk of collision is considered to be a head-on situation or an overtaking situation, as described in Rules 13 and 14.

This rule applies only between power-driven vessels, and not vessels which, for whatever reason, a power-driven vessel is directed to keep clear of or avoid impeding as described in Rule 18.

This rule also most emphatically does not apply in restricted visibility, the rules for which are covered exclusively by Rule 19 and the other sound and light signal rules towards the end of the Rules.

This rule states that a vessel which has the other on her own starboard side shall keep out of the way; this vessel is known as the ‘give-way vessel’. The other vessel is known as the ‘stand on vessel’. It is equally useful to think of this rule in reverse; that is, that the vessel that with the other on her port side should, as described in Rule 17, hold her current course and speed, and expect avoiding action to be taken by the other vessel.

This rule requires the give-way vessel to avoid, if possible, crossing ahead of the other vessel. Since she has the other on her starboard side, this means that more often than not the give-way vessel will make an alteration of course to starboard, although she is not forbidden by these rules to alter to port or even cross ahead of the other vessel, should it be necessary and safe to do so.

A crossing situation only exists if there is a risk of collision; it is not, paradoxically, a crossing situation if one vessel is going to cross the path of the other vessel so as for there to be no risk of collision.

 

Rule 16

 

Action by the give-way vessel

 

Every vessel which is directed to keep out of the way of another vessel shall, so far as possible, take early and substantial action to keep well clear.

 

Rule 15 requires a give-way vessel to keep out of the way, and in accordance with Rule 8, she should do this in ample time. This rule is therefore slightly superfluous, but it does make clear the necessity of taking early action. Rule 17 dictates the rules for action to be taken by stand-on vessels when give-way vessels are not taking sufficient avoiding action. That such action is required by this rule to be early allows the stand-on vessel identify when such action should have been taken by the give-way vessel, and therefore when she can safely take avoiding action.

This rule is not specifically meant to apply to vessels in a crossing situation, but it applies to all instances where one vessel is required to keep out of the way (keep clear) of another vessel. This is especially important with regards to Rule 18, which delineates the responsibilities between vessels. This rule does not however apply to vessels which are required not to impede the passage of another vessel. It also does not apply in conditions of restricted visibility. It does apply to all vessels, not specifically power-driven vessels.

 

Rule 17

 

Action by stand-on vessel

 

(a)       (i)         Where one of two vessels is to keep out of the way the other shall keep her course and speed.

 

Although this rule is lumped together with the rules for crossing vessels, and indeed is highly relevant in that case, this is a general rule, and is especially relevant not only to Rule 15 but also Rule 18, which describes the responsibilities between vessels.

This Rule means that where another vessel is required by these Rules to take avoiding action and keep clear, your vessel should hold her course and speed. This allows the other vessel to take decisive action; she cannot make a decision and follow it through safely if alterations of course are to occur.

 

            (ii)        The latter vessel may, however, take action to avoid collision by her manoeuvre alone, as soon as it becomes apparent to her the vessel required to keep out of the way is not taking appropriate action in compliance with these Rules.

 

Give-way vessels are required by Rule 16 and Rule 8 to take early and substantial action to keep well clear. If such action is not taken early, then she may take action to avoid collision herself without first giving any other form of indication or warning, although she must make the appropriate sound signals as described by Rule 34 if necessary for altering course or operating astern propulsion as normal.

Although a vessel, by this part of this Rule, may take action to avoid collision as soon as she determines that the other vessel is not going to take early action, she is not obliged to by this part of this Rule.

As per Rule 34 part (d), a vessel may make a signal consisting of at least five short and rapid blasts on the ship’s whistle, possibly accompanied by at least five short and rapid flashes with the ship’s light signalling appliance, before she takes action herself, which signals to the other vessel that she is not taking sufficient avoiding action and/or doubt exists as to the intentions of the avoiding vessel; she is not, however, obliged to do so.

Note that vessels that are for whatever reason to be kept clear of because they are unable to manoeuvre according to the Rules are still permitted to take avoiding action by this Rule, even if they cannot manoeuvre for whatever reason.

 

(b)       When, from any cause, the vessel required to keep her course and speed finds herself so close that collision cannot be avoided by the action of the give-way vessel alone, she shall take such action as will best aid to avoid collision.

 

Part (a)(ii) allows stand-on vessels to take avoiding action, but this part requires that they take such action. This Rule also applies to vessels that cannot manoeuvre according to the Rules; it does not stipulate that such action should necessarily consist of a manoeuvre.

At the very least, this action should consist of making the signal described in Rule 34 part (d) to alert the other vessel she is not taking sufficient action to avoid collision. If she is, however, able to make a manoeuvre, this Rule requires that she make such a manoeuvre. If a vessel cannot avoid a collision, then by carrying out the instructions of this Rule, she has obeyed the Rules, and she cannot be considered responsible for that collision, but this is only the case if she has taken whatever action which had best aided avoiding a collision; this means that any action she takes should be as early and as substantial as possible. Rule 2 specifically requires that a departure from the Rules may be necessary, and that even by following this Rule, she cannot be exonerated if a collision occurs.

 

(c)        A power-driven vessel which takes action in a crossing situation in accordance with subparagraph (a)(ii) of this Rule to avoid collision with another power-driven vessel shall, if the circumstance of the case admit, not alter course to port for a vessel on her own port side.

 

This rule only applies in a crossing situation, which only occurs between power-driven vessels. A vessel directed to keep out of the way of another in any other circumstances may alter course to port for a vessel on her own port side, if it is safe to do so.

This rule does not forbid vessels to alter port if it is necessary and safe to do so; it also does not forbid a vessel from making an alteration of course to port for a vessel other than the crossing vessel. It does, however, forbid making such an alteration of course if it is safe and possible to make an alteration of course to starboard, or if it is reasonably possible to avoid a collision by an alteration of speed.

 

(d)       This Rule does not relieve the give-way vessel of her obligation to keep out of the way.

 

The knowledge that if a give-way vessel does not keep out of the way the stand-on vessel will does not permit the give-way vessel to leave it to the stand-on vessel; she is still obliged to take early and substantial action to keep well clear.

 

Rule 18

 

Responsibilities between vessels

 

Except where Rules 9, 10 and 13 otherwise require:

 

This refers to exceptions made in these rules that require special action to be taken either by the stand-on or give-way vessel (as described by this Rule). These rules mentioned are the rules for narrow channels and fairways, traffic separation schemes, and overtaking situations. Rules 9 and 10 apply in any condition of visibility, and Rule 13 applies only in conditions outside of restricted visibility, but in restricted visibility, this Rule does not apply. This is partly because the type of vessel can only exactly be determined by the shapes and/or lights she is displaying, which in restricted visibility, by definition, another observing vessel will not be able to identify.

 

(a)       A power-driven vessel underway shall keep out of the way of:

           

Note that she does not have to be making way. A vessel stopped and making no way through the water is required adjust her speed and make way in order to avoid any incoming vessels as follows.

 

(i)         a vessel not under command;

            (ii)        a vessel restricted in her ability to manoeuvre;

            (iii)       a vessel engaged in fishing;

            (iv)       a sailing vessel.

 

Vessels not under command, or restricted in their ability to manoeuvre, or engaged in fishing, may be types of power-driven vessels but because their ability to manoeuvre is, by definition, hampered or absent, they aren’t required to keep out of the way of other vessels as required by this rule, or indeed any rule that requires something of power-driven vessels. An exception exists under part (c) of this rule for fishing vessels.

Such vessels may also be propelled, in normal circumstances, by sail, although in most situations in modern shipping, this will not be the case. There is no conflict caused by this under the Rules; such vessels are treated as such vessels first, and power-driven or sailing vessels second.

 

(b)       A sailing vessel underway shall keep out of the way of:

            (i)         a vessel not under command;

            (ii)        a vessel restricted in her ability to manoeuvre;

            (iii)       a vessel engaged in fishing.

 

Note that Rule 12 describes which of two sailing vessels shall keep out of the way of another. Power-driven vessels are normally obliged to keep out of the way of sailing vessels and not vice versa. In narrow channels and traffic separation schemes, sailing vessels are not required to keep out of the way of other vessels, but are required not to impede their passage, which is more fully described in Rules 9 and 10. Under Rule 13, if a sailing vessel is overtaking any other type of vessel, then Rule 13 applies, and she is directed to keep out of the way of the other vessel. She then becomes the give way vessel, and since Rule 13 ‘trumps’ other Rules, any type of other vessel then becomes the stand-on vessel and is therefore obliged to hold her course and speed.

 

(c)        A vessel engaged in fishing when underway shall, so far as possible, keep out of the way of:

            (i)         a vessel not under command;

            (ii)        a vessel restricted in her ability to manoeuvre.

 

The proviso that vessels engaged in fishing shall keep out of the way of vessels not under command or restricted in their ability to manoeuvre only if possible exists because fishing vessels are defined as such because their manoeuvrability is restricted, but not in such a way as prevents them from being able to manoeuvre as required by the Rules.

As with sailing vessels, Rules 9 and 10 require fishing vessels not to impede the passage of vessels in narrow channels or traffic separation schemes, and this is more fully described there. Other vessels are still obliged to keep clear of vessels engaged in fishing where a risk of collision exists, and not vice versa, but such risk of collision should not arise in accordance with those Rules.

 

(d)       (i)         Any vessel other than a vessel not under command or a vessel restricted in her ability to manoeuvre shall, if the circumstances of the case admit, avoid impeding the safe passage of a vessel constrained by her draught, exhibiting the signals in Rule 28.

 

This does not mean that they are directed to keep clear of or keep out of the way of such vessels, but that due to their actions, a risk of collision should not develop that requires them to take action to keep out of the way of such a vessel.

A vessel is only to be considered constrained by her draught if she is displaying the lights and/or shapes for a vessel constrained by her draught, as described in Rule 28. She may elect not to display such lights and shapes.

Vessels not under command and vessels restricted in their ability to manoeuvre are unable to take action to avoid impeding the passage of a vessel constrained by her draught and are thus not obliged to comply with this part of this Rule.

 

            (ii)        A vessel constrained by her draught shall navigate with particular caution having full regard to her special condition.

 

Other vessels shall only be obliged to take action to avoid impeding the safe passage of a vessel constrained by her draught when they are safely able to do so, as described in part (i) of this part.

Vessels constrained by their draught are able to alter course and speed, and therefore manoeuvre as required by the Rules. They are, most commonly (but not necessarily) confined to narrow channels. Such cannels are often not straight, but incorporate bends that a vessel must alter course to navigate along. Vessels constrained by their draught are also able to alter their speed to avoid a collision.

Because this is the case, all other Rules of part B apply to vessels constrained by their draught as normal for power-driven vessels. Only power-driven vessels can be considered constrained by their draught. The lights and shapes for a vessel constrained by her draught may only be in addition to the lights and shapes required for a power-driven vessels, so if a vessel does not and cannot display such lights, she cannot also be a vessel constrained by her draught.

Because of the allowances of this Rule, other vessels should take action to avoid forcing a vessel constrained by her draught to alter her course or speed, but if a risk of collision does develop, it can be assumed by the vessel constrained by her draught that such action was impossible and therefore that she is completely responsible for taking avoiding action herself as required by these Rules.

 

(e)       A seaplane on the water shall, in general, keep well clear of all vessels and avoid impeding their navigation. In circumstances, however, where risk of collision exists, she shall comply with the Rules of this part.

 

An aircraft designed to manoeuvre on the water is a seaplane. Most such craft will be power-driven vessels when on the water, since they will be propelled by propellers, which is a form of machinery. Theoretically, a water-borne glider or some other form of aircraft might be treated as a sailing vessel when on the surface of the water.

An aircraft, such as a balloon, that can land on the surface of the water but not manoeuvre on it is not considered a seaplane, not a vessel, as it cannot, under Rule 3, be considered capable of being used as a means of transportation over water. This Rule therefore does not apply in such a case.

 

(f)         (i)         A WIG craft, when taking off, landing and in flight near the surface, shall keep well clear of all other vessels and avoid impeding their navigation;

 

A WIG craft is directed to keep clear of other vessels and avoid impeding their navigation. This means that in their main operational mode, they are also considered to be power-driven vessels, and where risk of collision does exist, must be treated as such, although this should not happen under most circumstances, partly because of this rule.

 

            (ii)        A WIG craft operating on the water surface shall comply with the Rules of this Part as a power-driven vessel.

 

This is true whether or not the WIG craft is in its main operational mode. WIG crafts are much like aeroplanes, but are not seaplanes and when ‘flying’ are treated as power-driven vessels. This means that in addition to other vessels treating a WIG craft as a power-driven vessel, the vessel itself must behave in accordance with the rules for a power-driven vessel. This means that she must, in addition to keeping well clear of all other vessels and avoid impeding their navigation, obey the rules for traffic separation schemes as described in Rule 10, narrow channels as described in Rule 9, and the Rules for overtaking vessels in Rule 13, to name but a few, although all apply.

 

Section III – Conduct of vessels in restricted visibility

 

Rule 19

 

Conduct of vessels in restricted visibility

 

(a)       This Rule applies to vessels not in sight of one another when navigating in or near an area of restricted visibility.

 

This rule applies to all vessels equally because it is impossible to exactly identify vessels not in sight by their sound signals, as described in Rule 35, alone. Similarly, there is no way to distinguish them by radar.

There are no hard definitions of what constitutes restricted visibility, other than it should be when visibility is restricted by fog, sand or whatever, as per Rule 3. No ranges or distances are given, and it is up to the officer on watch to determine whether conditions of restricted visibility exist. In general, however, where a vessel cannot be seen that is nearby, or if conditions exist where a vessel might not be detected visually if it were present, then restricted visibility exists.

Certain vessels have different nominal ranges for their sound-signalling appliances. Where visibility is lower than this nominal range, conditions of restricted visibility absolutely exist. This is described more fully in the notes for Rule 35, and the nominal ranges are described for sound signalling appliances in Annex III part 1 (c).

Although there might be deemed to exist conditions of restricted visibility, wherever in such conditions two vessels can observe one another visually, the rules for section II, that is, governing the conduct of vessels in sight of one another, applies. This might happen, for example, when visibility is restricted to three miles.

Vessels in conditions of restricted visibility should make the appropriate sound signals for vessels of their type as described in Rule 35.

It is assumed that in conditions of restricted visibility, the primary means of detecting the existence and location of other vessels will be by radar, although not all vessels are required to be fitted with operational radar, and that such information gained by the radar may be incomplete. Rule 6, part (b), and Rule 7 have much to say on this subject. The other method of detecting other vessels in restricted visibility is by their sound signals. No other method counts; vessels, by definition, cannot detect one another visually in conditions of restricted visibility.

 

(b)       Every vessel shall proceed at a safe speed adapted to the prevailing circumstances and conditions of restricted visibility. A power-driven vessel shall have her engines ready for immediate manoeuvre.

 

The rules for safe speed are described in Rule 6. These Rules still apply, as they apply in all conditions of visibility. All vessels should at all times be able to alter their speed, except where they cannot, for example, due engine failure. A vessel may be not under command or restricted in its ability to manoeuvre, but it is not treated specially under this Rule. Generally, the engine room team prefer to know in advance when the telegraph might be used, so this rule is usually interpreted to mean that the engine team, in conditions of restricted visibility, shall know that it is likely the engine speed will be changed.

 

(c)        Every vessel shall have due regard to the prevailing circumstances and conditions of restricted visibility when complying with the Rules of section I of this part.

 

Again, the Rules of section I apply in all conditions of visibility. Therefore, they apply in this section, too. This part is a reminder; all vessels are direction to have due regard to the prevailing circumstances and conditions at all times (buzz-word; situational awareness!)

 

(d)       A vessel which detects by radar alone the presence of another vessel shall determine if a close-quarters situation is developing and/or risk of collision exists. If so, she shall take avoiding action in ample time, provided that when such action consists of an alteration of course, so far as possible the following action shall be avoided:

 

This rule means that any avoiding action may be taken, with the exception of such actions as described below. Note that vessels are not directed to ‘keep clear’ or ‘keep out of the way’, or ‘avoid impeding the passage or safe passage of another vessel’ or any other specified type of action; they are directed only to take ‘avoiding action’. This is important; there are no stand-on or give-way vessels in conditions of restricted visibility, and no rules of section II apply.

 

            (i)         an alteration of course to port for a vessel forward of the beam, other than for a vessel being overtaken;

 

Rule 9 requires that a vessel in a narrow channel or fairway make a sound signal when intending to overtake if the vessel to be overtaken has to take action to permit safe passing, but such a sound signal may only be made when two vessels can be observed visually from each other, and therefore a vessel may only overtake another in restricted visibility in a narrow channel when the other does not need to take any action to permit passage.

Note that if a vessel is detected forward of the beam, but an alteration of course needs to be made for a vessel not forward of the beam, then that is permitted, so long as it does not lead to another close-quarters situation developing. This especially complies with Rule 8 part (c).

Also note that although an alteration of course to starboard is permitted, it is not necessarily prudent to do so, especially when a vessel abeam is also off the starboard bow.

 

            (ii)        an alteration of course towards a vessel abeam or abaft the beam.

 

Although an alteration of course should not be made towards a vessel abeam or abaft the beam, this does not count when the other vessel is ‘finally past and clear’. It can be said to be so when no single alteration of course is likely to bring the two vessels close enough for risk of collision to exist.

Note that part (i) of this part forbids an alteration of course for a vessel forward of the beam, but this part forbids any alteration of course towards a vessel abeam or abaft the beam. Therefore, where a vessel exists, even if there is no immediate risk of collision (except for when the other vessel is finally past and clear) there can be no alteration of course towards it. A vessel that has another on both her port and starboard quarter may not alter course. A vessel which has another on her port bow may alter to port to avoid a vessel on her starboard quarter, but she may not alter to starboard, and she may not alter to port to avoid the vessel on her port bow.

 

(e)       Except where it has been determined that a risk of collision does not exist, every vessel which hears apparently forward of her beam the fog signal of another vessel, or which cannot avoid a close-quarters situation with another vessel forward of her beam, shall reduce her speed to the minimum at which she can be kept on her course. She shall if necessary take all her way off and in any event navigate with extreme caution until danger of collision is over.

 

In accordance with Rule 7 (a), if there is any doubt as to whether the sound signal has been detected forward of the beam or abaft it, the risk of collision shall be deemed to exist and appropriate action taken; in this case, reduce her speed to the minimum that she can be kept on course and if necessary, taking all her way off.

This part of this rule states that where it has been determined that a risk of collision does not exist, there is no need to reduce speed. This allows for one vessel to overtake another. It also allows for the fact that if a vessel forward of the beam is known to exist by radar, then it can be considered that there is no risk of collision; however, caution should be exercised when assuming this is the case as the size of the other vessel cannot be measured using the radar, and it nominal range is not known; it could be that a vessel is approaching that is not detected by radar. Rule 7 (c) says that assumptions shall not be made on the basis of scanty information, especially not scanty radar information. Assumptions of this nature generally should not be made, except where the reliability of the radar information has been determined to be high.

 

PART C – LIGHTS AND SHAPES

 

Rule 20

 

Application

 

(a)       Rules in this part shall be complied with in all weathers.

 

In other words, these Rules must be complied with whether in or outside of restricted visibility. Even if visibility is effectively nil, lights and shapes must be displayed. Because all vessels must remain visible at all times, according to this Rule, if a vessel that has been observed by radar that is not visible, it enables the officer on watch to judge ranges of visibility, which is extremely important in determining whether or not conditions of restricted visibility exist.

 

(b)       The Rules concerning lights shall be complied with from sunset to sunrise, and during such times no other lights shall be exhibited, except such lights as cannot be mistaken for the lights specified in these Rules or do not impair their visibility or distinctive character, or interfere with the keeping of a proper look-out.

 

This rule should be compared with Rule 1, part (c), which mentions that lights, shapes and whistle signals that are to be displayed in compliance with special rules should be such that they cannot be confused with any lights, shapes and whistle signals that are required to be displayed according to the Rules.

This rule should also be compared to Rule 36, which expounds upon signals to attract attention, and mentions that no such signals should be mistaken for any described elsewhere in these Rules. This can include the ‘navigational lights’ described in this part.

 

(c)        The lights prescribed by these Rules shall, if carried, also be exhibited from sunrise to sunset in restricted visibility and may be exhibited in all other circumstances when it is deemed necessary.

 

Note that vessels are required to display such lights in restricted visibility; it is not optional. It is optional at any other time, in other words, during the day in conditions of good visibility. Many vessels have their lights on all the time; this precludes the possibility of forgetting to activate them at night. In restricted visibility, lights are usually visible before the rest of the vessel is visible.

 

(d)       The Rules concerning shapes shall be complied with by day.

 

Note that whilst lights are required to be visible from sunset to sunrise, ‘day’ is a less well defined measurement of time. It may mean from morning twilight to evening twilight, in which case the time in which shapes must be displayed slightly overlaps the time in which lights must be displayed, which stands to reason since vessels should display their status at all times.

Shapes must be displayed in restricted visibility, but it is not required that they are displayed at night.

 

(e)       The lights and shapes specified in these Rules shall comply with the provisions of annex I to these Regulations.

 

Annex I covers the positioning and characteristics of lights and shapes. These positions are described in the main bulk of the Rules, but exact requirements are given in annex I. These regulations should be at least roughly familiar to the mariner, as, especially with smaller vessels, the positioning of lights and shapes may be somewhat surprising and can vary to quite a degree. Exact values of chromaticity, brilliance and so forth aren’t measurable at sea, and are provided for the shipbuilder’s concern. Additionally, the exact spacing of lights and shapes is provided for the shipbuilder’s concern; it is enough that the mariner is able to recognise the vessel type and aspect of another vessel.

 

Rule 21

 

Definitions

 

All lights are displayed show as to show one of four navigational light sector types. These are; masthead lights, sidelights, stern lights, and all-round lights.

 

 

As this illustration depicts, the sidelight sectors combine to form the masthead light sector, abaft of which there exists the sternlight sector. All-round lights form an unbroken arc of light projecting 360° around the vessel. This is explained below more thoroughly, but it is worth remembering that the forward sectors extend to 22.5° abaft the beam. From this, the arcs of all other sectors can be calculated, if need be, and easily described in those terms.

 

 

(a)       Masthead light means a white light placed over the fore-and-aft centreline of the vessel showing an unbroken light over an arc of the horizon of 225° and so fixed as to show the light from right ahead to 22.5° abaft the beam on either side of the vessel.

 

Note that this rule, as with all other rules concerning lights and shapes, may be modified by Rule 1 (e) which governs vessels of special construction. This particular rule is easy to remember as the arc extends 10% of its totality abaft the beam on either side of the vessel (in other words, 225° ÷ 10 = 22.5°.)

 

(b)       Sidelights means a green light on the starboard side and a red light on the port side each showing an unbroken light over an arc of the horizon of 112.5° and so fixed as to show the light from right ahead to 22.5° abaft the beam on its respective side. In a vessel of less than 20m in length the sidelights may be combined in one lantern carried on the fore-and-aft centreline of the vessel.

 

The latter part of this rule may be modified, as per Rule 23 part (d) and Rule 25 part (b) and part (c).

 

(c)        Sternlight means a white light placed nearly as practicable at the stern showing an unbroken light over an arc of the horizon of 135°, and so fixed as to show the light 67.5° from right after on each side of the vessel.

 

(d)       Towing light means a yellow light having the same characteristics as the sternlight defined in paragraph (c) of this Rule.

 

The towing light is shown as described in Rule 24 as required. Although this rule states that it has the same characteristics as a sternlight, it is always shown in a vertical line above the sternlight. The ‘same characteristics’ is meant to mean that it must be of equivalent intensity, as required by Rule 22.

 

(e)       All-round light means a light showing an unbroken light over an arc of the horizon of 360°.

 

Note that as all-round lights may be of any colour as required by the rules, no colour is described here.

 

(f)         Flashing light means a light flashing at regular intervals at a frequency of 120 flashes or more per minute.

 

Flashing lights are used in these rules to indicate WIG craft and hovercraft; that is, air-cushioned vessels operating in non-displacement mode. Hovercraft display an all-round flashing yellow light, and WIG craft a high-intensity all-round flashing red light, as described in Rule 23 (b) and (c).

Annex II part 3 describes the light signals to be displayed by purse seiners, a type of fishing vessel. These are described as two yellow lights in a vertical line that flash alternately every second and with equal light and occultation duration. Although these are described as lights that flash, they are not ‘flashing’ as these Rules describe.

 

Rule 22

 

Visibility of lights

 

The lights prescribed in these Rules shall have an intensity as specified in section 8 of annex I to these Regulations so as to be visible at the following minimum ranges:

 

Annex I describes the luminosity in candelas for each type of light at each specified range. There is a formula for this. As seafarers cannot identify luminosity, it can be safely assumed that they aren’t required to remember the requirements for different lights in those terms; instead, they ought only to remember the nominal ranges of different lights in nautical miles. The luminosity data is meant for shipbuilders.

Note that this rule describes minimum ranges; the seafarer can expect to detect other vessels by their lights at much longer ranges in optimal conditions.

 

(a)       In vessels of 50m or more in length:

            -           a masthead light, 6 miles;

            -           a sidelight, 3 miles;

            -           a sternlight, 3 miles;

            -           a towing light, 3 miles;

            -           a white, green, or yellow all-round light, 3 miles.

 

Vessels that become visible at the nominal ranges described might not be identifiable until they come closer. For example, if a target is identified by radar at a range of 3 miles, approaching, and a single white light suddenly becomes visible, then it could be any number of vessels, at any aspect. Within 1 mile, however, all lights belonging to any type of vessel become identifiable.

This isn’t to say that useful information can’t be gleaned at greater ranges. If the aforementioned single white light becomes visible at 3 miles, it might be, for example, the single masthead light of a power-driven vessel of 30m in length; but if, at 2 miles, one or both of its sidelights are not visible, then it cannot be the single masthead light of such a vessel; it must be a different type of vessel or at a different aspect.

 

(b)       In vessels of 12m or more in length but less than 50m in length:

 

-                      a masthead light, 5 miles; except that where the length of the vessel is less than 20m, 3 miles;

-                      a sidelight, 2 miles;

-                      a sternlight, 2 miles;

-                      a towing light, 2 miles;

-                      a white, red, green or yellow all-round light, 2 miles.

 

Note that effectively two categories of vessel are described here, vessels between 20m and 50m in length and vessels between 12m and 20m in length.

 

(c)        In vessels of less than 12m in length:

           

-           a masthead light, 2 miles;

            -           a sidelight, 1 mile;

            -           a sternlight, 2 miles;

            -           a towing light, 2 miles;

            -           a white, red, green or yellow all-round light, 2 miles.

 

In conditions outside of restricted visibility, a vessel of any type will be visible at a range of 2 miles. Not all vessels display masthead lights, but if they do not, they will be displaying some form of all-round light. If a vessel is detected by radar, and it is not visible at a range of 2 miles, then it is certain that conditions of restricted visibility exist.

 

(d)       In inconspicuous, partly submerged vessels or objects being towed:

            -           a white, all-round light, 3 miles.

 

This part of this rule refers specifically to Rule 24 part (g). It does not refer to, for example, submarines that have breached, and are therefore partly submerged vessels, but are not being towed; in this example, such a vessel would be lighted as a power-driven vessel of its length.

 

The descriptions of the nominal ranges of the lights of vessels of different lengths are a somewhat cumbersome way of expressing the nominal ranges of the lights of those vessels. This table expresses the same information differently:

 

                                Vessel > 50m         Vessel < 50m         Vessel < 20m         Vessel < 12m

Masthead light       6 nm                       5 nm                       3 nm                       2 nm

Sidelight                 3 nm                       2 nm                       2 nm                       1 nm

Sternlight                3 nm                       2 nm                       2 nm                       2 nm

Towing Light         3 nm                       2 nm                       2 nm                       2 nm

All-round light      3 nm                       2 nm                       2 nm                       2 nm

 

Rule 23

 

Power-driven vessels underway

 

(a)       A power-driven vessel underway shall exhibit:

           

            (i)         a masthead light forward;

            (ii)        a second masthead light abaft of and higher than the forward one; except that a vessel of less than 50m in length shall not be obliged to exhibit such a light but may do so;

            (iii)       sidelights;

            (iv)       a sternlight.

 

A power-driven vessel is defined in Rule 3, definitions, and includes a sailing vessel that is also using its engines, if fitted. A power-driven vessel is lit in this way, but it may be lit in other ways in certain circumstances, such as if it is not under command. Unless otherwise stated, if a vessel is lit in some other way, it will not be lit as a power-driven vessel unless the particular rule in question states that it shall be. See Rule 24, 26, 27, 28, 29 and 30.

A power-driven vessel, more than 50m in length, seen from astern. Vessels of less than 50m in length may exhibit these lights, but are not obliged to.

 

 

 

 

 

 

A power-driven vessel, more than 50m in length, seen from right forward. Vessels of less than 50m in length may exhibit these lights, but are not obliged to.

 

 

 

 

 

 

 A power-driven vessel, more than 50m in length, seen from the starboard side. Vessels of less than 50m in length may exhibit these lights, but are not obliged to.

 

 

 

 

 

 

A power-driven vessel, more than 50m in length, seen from the port side. Vessels of less than 50m in length may exhibit these lights, but are not obliged to.

 

 

 

 

 

 

A power-driven vessel, less than 50m in length, seen from astern.

 

 

 

 

 

 

A power-driven vessel, less than 50m in length, seen from right forward.

 

 

 

 

 

 

 A power-driven vessel, less than 50m in length, seen from the starboard side.

 

 

 

 

 

 

A power-driven vessel, less than 50m in length, seen from the port side.

 

 

 

 

(b)       An air-cushioned vessel when operating in the non-displacement mode shall, in addition to the lights prescribed in paragraph (a) of this Rule, exhibit an all-round flashing yellow light.

 

Note that no location is given for this light, but it must be visible from every angle. It is not required to be placed where can best be seen, nor as a masthead light, forward masthead light, sternlight, or any other place; anywhere will do.

 

(c)        A WIG craft only when taking off, landing and in flight near the surface shall, in addition to the lights prescribed in paragraph (a) of this Rule, exhibit a high-intensity all-round flashing red light.

 

Again, as with hovercraft, the high-intensity flashing red light does not need to be placed in any specific location. WIG crafts especially, and to some extent hovercraft, are vessels of special construction, and where the government of any state shall have determined that such a vessel cannot comply fully with the characteristics and locations of lights and shapes as required by the Rules (as stated in Rule 1, part (e)) she shall instead have the locations and characteristics of those lights and shapes as closely resembling those required by these Rules as possible; therefore, WIG craft and hovercraft are likely to appear unusually when view at night, but must otherwise comply with the rules of this Rule in every way.

The flashing red light described in this Rule is the only example of a high-intensity light in the Rules. Nowhere in the Rules is it stated what constitutes a ‘high-intensity light’, but annex I of the Rules mentions, in passing, that any light’s luminosity should be such as to prevent ‘undue glare’.

 

(d)       (i)         A power-driven vessel of less than 12m in length may in lieu of the lights prescribed in paragraph (a) of this Rule exhibit an all-round white light and sidelights;

 

Such a vessel will normally have the all-round white light displayed in the fore-and-aft centreline of vessel, as mentioned in part (iii) of this part of this Rule. This part does not require that such an all-round light should be placed on the masthead, although since it is an all-round light it most likely will be. This part of this Rule is an ‘either one or the other’ rule, and thus precludes having a second mast-head light. The single, all-round white light replaces both the masthead light and the sternlight, and may be in either or neither location. It will still be possible to judge the aspect of such a vessel from its sidelights.

Illustrations for part (d) of this Rule are not provided as there are too many legal permutations of carried lights.

 

            (ii)        a power-driven vessel of less than 7m in length whose maximum speed does not exceed 7 knots may in lieu of the lights prescribed in paragraph (a) of this Rule also exhibit an all-round white light and shall, if practicable, also exhibit sidelights;

 

This part is effectively a restatement of part (i), except that power-driven vessels of less than 7m in length are not required to display sidelights. The phrasing of this Rule is such that vessels are required to display the sidelights if it is at all feasible to do so.

Remember that a single white light can mean many different things at any range, and may be confused for a shore light.

 

            (iii)       the masthead light or all-round white light on a power-driven vessel of less than 12m in length may be displaced from the fore-and-aft centreline of the vessel if centreline fitting is not practicable, provided that the sidelights are combined in one lantern which shall be carried on the fore-and-aft centreline of the vessel or located as nearly as practicable in the same fore-and-aft line as the masthead light or the all-round white light.

 

Note that the single combined lantern may only be carried if the masthead light or lights or all-round white light are not carried on the fore-and-aft centreline of the vessel, and where this is the case, the sidelights must be combined into one lantern, which may be carried either on the fore-and-aft centreline, or the same fore-and-aft line as where the single white all-round light or masthead light or lights are carried.

 

Rule 24

 

Towing and pushing

 

(a)       A power-driven vessel when towing shall exhibit:

            (i)         instead of the light prescribed in Rule 23(a)(i) or (a)(ii), two masthead lights in a vertical line. When the length of the tow, measure from the stern of the towing vessel to the after end of the tow, exceeds 200m, three such lights in a vertical line;

            (ii)        sidelights;

            (iii)       a sternlight;

            (iv)       a towing light in a vertical line above the sternlight;

            (v)        where the length of the tow exceeds 200m, a diamond shape where it can best be seen.

 

Vessels engaged in towing other vessels or objects are still to be considered power-driven vessels, and although they do not comply with Rule 23(a) part (i), they do, as part (d) of this Rule states, comply with Rule 23(a)(ii), contrary to what this part of this Rule states.

This part of this Rule only applies to a vessel towing another vessel or object behind it, and does not apply to a vessel towing another alongside, or a vessel pushing another ahead, unless those vessels are also towing other vessels behind. The rules covering those types of vessels are also described in this part.

In restricted visibility, vessels engaged in any type of towing or pushing ahead make the same sound signal. This is described in Rule 35. However, only vessels or objects towed behind make sound signals, and only if manned, and only the last of such objects in a tow makes such a sound signal. This is described more fully in the notes for that Rule.

When the towing vessel is restricted in its ability to manoeuvre, Rule 27(c) applies, which requires the vessel to display the characteristic lights and shapes of a vessel restricted in its ability to manoeuvre. The towing vessel does not always display such lights. It can be considered a vessel restricted in its ability to manoeuvre under all other Rules, but although it displays the red, white, and red all-round lights in a vertical line and/or the ball, diamond and ball in a vertical line, it is not otherwise lit as a vessel restricted in its ability to manoeuvre, but as a power-driven vessel that is also towing, and happens to be restricted in its ability to manoeuvre.

 

(b)       When a pushing vessel and a vessel being pushed ahead are rigidly connected in a composite unit they shall be regarded as a power-driven vessel and exhibit the lights prescribed in Rule 23.

 

This only applies to pushing vessels and the vessels to which they are connected, and not any type of towing vessel. Part (f) of this Rule does not also apply.

 

(c)        A power-driven vessel when pushing ahead or towing alongside, except in the case of a composite unit, shall exhibit:

           

(i)         instead of the light prescribed in Rule 23(a)(i) or (a)(ii), two masthead lights in a vertical line;

            (ii)        sidelights;

            (iii)       a sternlight.

 

A vessel engaged in pushing another vessel or vessels or objects or towing them alongside is not regarded as a towing vessel, and is not lit as such, but may be lit similarly. They do not display towing lights; only vessels towing something behind display the towing light. The length of the tow or vessel being pushed ahead does not affect how many lights or shapes the vessel shows, and the vessel will never display three masthead lights or a diamond.

This rule does not, however, preclude the possibility that vessel pushing another ahead or towing alongside may also be towing another vessel or object. If that is the case, they will show the towing light as well, and may also show a third masthead light forward or a diamond if the length of the objects being towed exceeds 200m.

 

(d)       A power-driven vessel to which paragraph (a) or (c) of this Rule applies shall also comply with Rule 23 (a)(ii).

 

This is probably the oddest rule described in the Rules. Parts (a) and (c) of this Rule specifically state that power-driven vessels engaged in towing or pushing should not obey Rule 23(a)(ii), and show a second masthead light; this Rule, on the other hand, requires them to, but they are still not obliged if less than 50m in length.

 

(e)       A vessel or object being towed, other than those mentioned in paragraph (g) of this Rule, shall exhibit:

            (i)         sidelights;

            (ii)        a sternlight;

            (iii)       when the length of the tow exceeds 200m, a diamond shape where it can best be seen.

 

Note that this rule does not apply to vessels being pushed ahead. It does not specifically preclude vessels or objects towed alongside, either, although the rules covering vessels (and not objects) towed alongside are described in part (f) of this Rule, and are similar to this Rule in that instance except that no mention of diamond shapes is made . Each vessel or object being towed displays its own lights. Although both tug and tow display a diamond shape when the length of the tow exceeds 200m, the tow does not display an additional light, as the tug does on its forward masthead.

There is a peculiar irregularity here. When a towing vessel is towing any number of vessels or objects, the length of the tow is measured from the stern of the towing vessel to the stern of the last vessel or object being towed. If this distance exceeds 200m, she shows an additional masthead light forward, and/or a diamond where it can best be seen. If there is only one vessel or object being towed, and its length exceeds 200m, then it clearly must display a diamond from where it can best be seen. However, where there are several smaller objects that come to more than 200m, it is not clear as to whether they should, or should not, display a diamond shape, and if so, on which vessel or object the shape should be displayed, if not on all. If only one such diamond is to be displayed, then it may be that it must be displayed from where can best be seen on any of the vessels or objects in tow.

It may be that if the length of a specific vessel or object being exceeds 200m, then that object, regardless of whether there are other vessels or objects being towed, displays the diamond shape. As this interpretation conveys the most information, the author regards this as the most likely interpretation. Therefore, a towing vessel that displays the diamond shape might be encountered with vessels being towed that do not display the diamond, or that display more than one.

It is not immediately clear whether part (iii) of this Rule applies to vessels being towed alongside or not. Part (f) of this Rule states that where several vessels are being towed alongside, they shall be lit as a single vessel. If it is interpreted that vessels being towed alongside are being towed and therefore that this Rule does apply, then since part (f) only covers vessels, and details only how they should be lit, not mentioning shapes, then each vessel towed alongside should display a diamond shape if longer than 200m individually, if the aforementioned interpretation is accepted. If not, however, only diamond shape, if any, should be shown, from where can best be seen on any vessel, if any vessel is greater than 200m in length. Because the vessels and/or objects are towed alongside, their cumulative length of the vessels and objects is irrelevant.

Part (h) of this Rule allows for vessels or objects that cannot practicably be lit according to this Rule to be lit as best they can be, or at least for the presence of the vessel or object to be indicated.

 

 

(f)         Provided that any number of vessels being towed alongside or pushed in a group shall be lighted as one vessel,

 

This states that such vessels shall be lighted as one vessel, and that where this is the case, the following Rules shall be followed. This rule applies not just to several vessels, but any singular vessel being pushed ahead or towed alongside, and does not apply to any objects. It also does not, as mentioned in the notes for part (e) of this Rule, govern the placement of any types of shapes.

 

            (i)         a vessel being pushed ahead, not being part of a composite unit, shall exhibit at the forward end, sidelights;

 

This part clarifies that part (f) does not apply if part (b) does. The vessels being pushed ahead displays sidelights, and only sidelights, and only at the forward end, and can cover any number of vessels of any length. This rule does not explicitly include objects; therefore, any type of object being pushed ahead need not be lit at all.

 

            (ii)        a vessel being towed alongside shall exhibit a sternlight and at the forward end, sidelights.

 

Note that unless vessels or objects towed alongside are to be considered vessels or objects being towed, then objects that are not inconspicuous or partly submerged are not lit at all, but if they are, part (e) would apply, and they would be lit separately, whereas vessels towed alongside, following this part, are lit as one. If part (e) is deemed not to apply to such objects, then part (g) ought not to apply, either, but if it is, it applies only inconspicuous or partly submerged objects.

The author’s view is that vessels or objects towed alongside are considered vessels or objects being towed, and are lit as described in part (e), and also display the shapes described in part (e). Without this interpretation, objects being towed alongside or pushed ahead are unlit, which is clearly more dangerous than the contrary, and henceforth the spirit of the Rules is complied with to a greater extent. Under this interpretation, partly submerged and/or inconspicuous vessels and objects being towed alongside also obey part (g) of this Rule.

Another peculiarity of this Rule is that vessels being towed alongside, whilst they must be lighted as one vessel, may not be on the same side of the towing vessel and if treated as one vessel, in any case, the fore-and-aft centreline of such a combined vessel is likely to exist apart from the actual fore-and-aft centreline of any of the composite vessels.

There are two possible solutions to this problem. The first is that the Rules are to be complied with to the letter, such that such a combined vessel is lit exactly as the rules require. The starboardside most vessel displays its starboard sidelight, the portside most vessel displays its port sidelight, and some way is found of suspending a sternlight between the two vessels furthest out so that the stern light can be displayed exactly upon a line which is laterally equidistant from both sidelights. Such a sternlight might be suspended from a cable, or if luck should so have it, may be displayed from a vessel which straddles the theoretical combined centreline.

The other possible solution is to simply display such lights as most closely follow the Rules, treating the combined vessel as a vessel of ‘special construction’. Such an arrangement may need to be approved by ‘the government of any state’, as required by Rule 1 part (e).

 

(g)       An inconspicuous, partly submerged vessel or object, or combination of such vessels or objects being towed, shall exhibit:

 

Part (e) of this Rule specifically mentions that objects covered by part (g) of this Rule are exempt from the need to comply with part (e). Part (h), as with part (e), allows for vessels that cannot practicably be lit according to the requirements of this part of this Rule to be lit as well as possible, or at least their presence somehow indicated.

           

            (i)         if it is less than 25m in breadth, one all-round white light at or near the forward end and one at or near the after end except that dracones need not exhibit a light at or near the forward end;

 

A dracone is a bag that is used to transport bulk liquids, usually oil or its products, through the water. The forward and after ends of the object being towed should be along the centreline of the object, which should be in line with the centreline of the towing vessel.

 

            (ii)        if it is 25m or more in breadth, two additional all-round white lights at or near the extremities of its breadth;

 

The object may be of any shape, so that the extremities of the object’s breadth might be closer to the stern than the forward end; or, the greatest extremity of its breadth might be closer to the forward end on the port side, and closer to the stern on the starboard side. The greatest extremity of the breadth of the vessel is a the greatest lateral distance from the fore-and-aft centreline of the vessel. The fore-and-aft centreline of the vessel should be in line with the fore-and-aft centreline of the towing vessel.

 

            (iii)       if it exceeds 100m in length, additional all-round white lights between the lights prescribed in subparagraphs (i) and (ii) so that the distance between the lights shall not exceed 100m;

 

Note that the maximum distance between lights is 100m, and that these additional lights are placed between not only the lights at either end, but between the lights at the extremities of its breadth, as well.

This part of this rule does not apply until the length of the vessel or object being towed exceeds 100m. If the breadth exceeds 100m, then no additional lights need be placed.

This rule is a little vague as to where exactly the lights ought to be placed. There are several possible interpretations of this Rule. Note that if an object is greater than 100m in length, but less than 25m in length, no lights are to be placed at the extremities of the vessel’s breadth, and therefore additional lights will be placed on the fore-and-aft centreline of the vessel. In this case, there is only one, straightforward interpretation of this Rule.

Where lights are placed at the extremities of the vessel’s breadth, if the vessel is greater than 100m in length, the vessels at the extremities of its breadth may be less than 100m from the lights at either end of the vessel’s length. In this case, although the distance between the lights is less than 100m, additional lights still need to be placed, as the vessel is more than 100m in length, and therefore part (iii) must be followed.

It can be interpreted that the additional lights must be placed on the midpoints of each line formed upon an imaginary quadrangle the corners of which consist of each light at the forward, aft, and each extreme end of breadth of the object being towed. The problem with this interpretation is that, for a very large object, there would be an area in the centre that remains unlit; although, since each light is within 100m of another light, it still complies with the Rule.

Another interpretation is that lights are placed along the fore-and-aft centreline of the vessel, and along an imaginary line between the extremities of the breadth of the vessel. Under this interpretation, two all-round white lights might need, for example, to be placed next to each other on an object at or just over 100m long and wide, and on a particularly large object, the port bow, starboard bow, port quarter and starboard quarter would remain unlit, yet still, each light would be within 100m of every other light.

A third interpretation is that the exact placement of the additional lights disregards the exact position of the forward and aft lights, and the lights at the extreme breadth of the vessel, and that additional lights are placed in whatever location is deemed most practical, so long as at least one additional light is placed where the vessel is 100m long or longer, probably in the centre of the vessel.

The third interpretation seems the most likely, and by definition, the most practical, and does indeed comply with the Rules, since it complies both with part (i) and (ii) and ensures that no light is greater than 100m from any other light. It does mean, however, that there might be a dazzling variety of configurations of lights that the observant mariner must look out for.

 

            (iv)       a diamond shape at or near the aftermost extremity of the last vessel or object being towed and if the length of the tow exceeds 200m an additional diamond shape where it can best be seen and located as far forward as is practicable.

 

It is clear where the aftermost diamond shape ought to be placed, but there is still some confusion as to whether the diamond shape ought to be placed forward and from where it can best be seen on only the closest object to the towing vessel if the entire length of the tow exceeds 200m, or only on an object that exceeds 200m in length, and possibly on several objects if more than one exceeds 200m in length.

The author tends to think that this Rule is to be interpreted to mean that any singular object that is greater than 200m in length should display on it a diamond shape forward from where it can best be seen. This conveys the most useful information.

 

(h)        Where from any sufficient cause it is impracticable for a vessel or object being towed to exhibit the lights or shapes prescribed in paragraph (e) or (g) of this Rule, all possible measure shall be taken to light the vessel or object towed or at least to indicate the presence of such vessel or object.

 

This rule does not apply to vessels that normally are not engaged in towing other vessels, and that are, for example, towing another vessel because of some emergency on board that vessel. This Rule applies mainly to vessels that normally are engaged in towing. It may be impracticable to light the vessel being towed, but it is assumed that the towing vessel will have some means of lighting or at least indicating the presence of the towed vessel on board as part of her regular equipment.

 

(i)         Where from any sufficient cause it is impracticable for a vessel not normally engaged in towing operations to display the lights prescribed in paragraph (a) or (c) of this Rule, such vessel shall not be required to exhibit those lights when engaged in towing another vessel in distress or otherwise in need of assistance. All possible measures shall be take to indicate the nature of the relationship between the towing vessel and the vessel being towed as authorised by Rule 36, in particular by illuminating the towline.

 

Rule 36 is the Rule governing signals to attract attention, and states that any light or sound signal so used so as to attract attention should not be mistakable for any other light or sound signal in the Rules and also not mistakable for any aid to navigation, or ‘embarrass’ any vessel, which in this context means to interfere with another vessel’s watch, for example by blinding another officer on watch and ruining his night vision.

This Rule emphatically only applies to vessels that are not normally engaged in towing, and are towing to assist another vessel, for example, on in distress. Otherwise, part (h) applies. This part of this Rule authorises signals to attract attention under Rule 36, whereas part (h) does not; both these Rules apply equally to towing vessels and vessels being towed.

 

Towing vessel, less than 50m in length, length of tow, less than 200m in length, seen from the port side.

 

 

 

 

 

 

Towing vessel, less than 50m in length, length of tow, more than 200m in length, seen from the port side.

 

 

 

 

 

Towing vessels less than 50m in length may show a second masthead light abaft of and higher than the two masthead lights forward, but a vessel 50m in length must show it; tow, less than 200m in length, seen from the port side.

 

 

 

 

 

Towing vessels less than 50m in length may show a second masthead light abaft of and higher than the two masthead lights forward, but a vessel 50m in length must show it; tow, more than 200m in length, seen from the port side.

 

 

 

 

 

Rule 25

 

Sailing vessels underway and vessels under oars

 

(a)       A sailing vessel underway shall exhibit:

            (i)         sidelights

            (ii)        a sternlight

 

There are several vessels and objects that show sidelights and a sternlight, but no masthead lights, including vessels or objects being towed as described in Rule 24. In addition, vessels not under command when making way display sidelights and a sternlight, but no masthead lights, but also two all-round red lights in a vertical line where they can best be seen; also, when making way, a pilot vessel shows sidelights and a sternlight, but no masthead lights, but also shows one white all-round light and below, one red all-round light in a vertical line at the top of the masthead.

Nothing in the Rules precludes a sailing vessel from also being a fishing vessel, a vessel not under command, a vessel restricted in her ability to manoeuvre, a vessel engaged in dredging or underwater operations, a pilot vessel, or a vessel at anchor. A seaplane may even be considered a sailing vessel.

Sailing vessels cannot display the lights that indicate that they are vessels constrained by their draught, vessels engaged in towing, towing alongside or pushing ahead unless they are also being propelled by machinery and thus displaying the lights for a power-driven vessel instead of the lights for a sailing vessel, for it is stated that such a vessel shall be considered a power-driven vessel under Rule 3 part (c). Also, for the same reason, a sailing vessel may not display the lights that would indicate that she is a vessel engaged in mineclearance operations unless she is also at anchor.

The reason for this is that the aforementioned lights must be shown in addition to the lights for a power-driven vessel. They cannot be shown in addition to the lights for a sailing vessel, and a sailing vessel may not show the lights for a power-driven vessel, unless she is using her propelling machinery.

A sailing vessel is not prohibited from towing, towing alongside or pushing, but this may not be feasible and in any case she shows no lights or shapes to indicate this.

A sailing vessel must indicate that she is engaged in fishing, not under command, restricted in her ability to manoeuvre, engaged in dredging or underwater operations, engaged in mine clearance operations, constrained by her draught, engaged in pilotage duties, at anchor, or aground by hoisting the appropriate shapes, if she is engaged in that activity.

These rules are described under Rules 24, 26, 27, 29 and 30. Note that sailing vessels may not be practically suited for many of these tasks, and may be unlike to find themselves in any of these adverse statuses, but that they are not prohibited from engaging in them merely because the rules do not require them to indicate that they are so engaged.

Rule 27 part (g) lifts many of the specific restrictions required under Rule 27 for vessels under 12m in length.

 

(b)       In a sailing vessel of less than 20m in length the lights prescribed in paragraph (a) of this Rule may be combined in one lantern carried at or near the top of the mast where it can best be seen.

 

Note that power-driven vessels of less than 12m in length, as mentioned in Rule 23(d)(iii), must combine their sidelights into one lantern that is carried on the centreline or the same fore-and-aft line as the masthead light or single all-round white is carried, if the masthead light or single all-round white light is displaced from the centreline of the vessel. Such a vessel can be distinguished from a sailing vessel by the aforementioned masthead light or all-round white light.

 

(c)        A sailing vessel underway may, in addition to the lights prescribed in paragraph (a) of this Rule, exhibit at or near the top of the mast, where they can best been seen, two all-round lights in a vertical line, the upper being red and the lower green, but these lights shall not be exhibited in conjunction with the combined lantern permitted by paragraph (b) of this Rule.

 

These lights confirm that vessel is, unambiguously, a sailing vessel.

 

(d)       (i)         A sailing vessel of less than 7m in length shall, if practicable, exhibit the lights prescribed in paragraph (a) or (b) of this Rule, but if she does not, she shall have ready at hand an electric torch or light lantern showing a white light which shall be exhibited in sufficient time to prevent collision.

 

Small sailing vessels are not relieved from their requirement to show the lights required by larger sailing vessels by this Rule; they must do so if it is practicable. In the event of collision, if she did not use an electric torch to indicate her presence and thus allow another vessel to recognise her and take avoiding action to prevent a collision, she is considered fully responsible for the collision occurring.

 

            (ii)        A vessel under oars may exhibit the lights prescribed in this Rule for sailing vessels, but if she does not, she shall have ready at hand an electric torch or light lantern showing a white light which shall be exhibited in sufficient time to prevent collision.

 

This rule is similar to part (i) of this part, but it is important in that any vessel under oar of any size may show lights as a sailing vessel but is not obliged to do so, but if not, must indicate her presence in order to prevent a collision from occurring if need be.

Most vessels under oars will be small, but it is not impossible that a larger vessel might exist; for example, a historical recreation of a trireme.

Vessels under oars are not forbidden from engaging in the activities and being considered under the statuses described in the notes for part (a) of this Rule, that is, if Rules 24, 26, 27, 28, 29 and 30 apply. Vessels under oars are not required to display the lights of a sailing vessel, but they are required to display any lights and shapes required by Rules 26, 27, 29 and 30, even if they are not required to display the lights for a sailing vessel.

 

(e)       A vessel proceeding under sail when also being propelled by machinery shall exhibit forward where it can best be seen a conical shape, apex downwards.

 

If propelling machinery is being used, the vessel is considered a power-driven vessel and must display the lights for power-driven vessels under Rule 23. This can be confirmed by Rule 3 part (c).

 

 

Two sailing vessels, side-by-side, seen from right ahead, both of which are less than 20m in length. Sailing vessels of less than 7m in length should if practicable display such lights, and vessels under oars may also choose to do so.

 

 

 

Rule 26

 

Fishing vessels

 

(a)       A vessel engaged in fishing, whether underway or at anchor, shall exhibit only the lights and shapes prescribed in this Rule.

 

This rule applies whether the vessel is power-driven or treated as under sail. Vessels at anchor are not underway, but more importantly, they are stopped and making no way through the water. Note that a vessel engaged in fishing, by this Rule, is required to display certain lights and shapes, even if it is not underway. Rules 23 and 25, governing power-driven and sailing vessels, only apply when underway.

A vessel engaged in fishing is only considered as such when, according to Rule 3, it is fishing with nets, lines, trawls, or any other fishing apparatus which restricts manoeuvrability, but not trolling lines or other apparatus which does not restrict manoeuvrability.

Also note that whilst a fishing vessel has restricted manoeuvrability, it is NOT considered a vessel restricted in its ability to manoeuvre. Rule 18 describes the responsibilities between vessels, in which, under part (c), fishing vessels are required to (to the best of their ability) keep clear of vessels not under command or restricted in their ability to manoeuvre. Where they not able to manoeuvre according to the Rules, this would be impossible; hence, fishing vessels are considered able to manoeuvre. If they are not able to manoeuvre at all, under this part of this Rule, they do not display any special lights or shapes to indicate so. Thus, other vessels must treat them only as fishing vessels (which usually means they must keep well clear.)

 

(b)       A vessel when engaged in trawling, by which is meant the dragging through the water of a dredge net or other apparatus used as a fishing appliance, shall exhibit:

 

            (i)         two all-round lights in a vertical line, the upper being green and the lower white, or a shape consisting of two cones with their apexes together in a vertical line one above the other;

            (ii)        a masthead light abaft of and high than the all-round green light; a vessel of less than 50m in length shall not be obliged to exhibit such a light but may do so;

            (iii)       when making way through the water, in addition to the lights prescribed by this paragraph, sidelights and a sternlight.

 

Only trawlers exhibit the green-over-white light, and only they display the second masthead light; they never display the single white all-round light that indicates outlying gear.

The white and green all-round lights need be displayed anywhere on the vessel. Convention places them forward, but they may be anywhere, and not necessarily where can best be seen. Vessels larger than 50m must have a masthead abaft of and higher than these vertical lights, which places them forward.

Part (d) of this mentions annex II. Annex II only applies to vessels fishing within a fleet.

Annex II requires of trawlers greater than 20m in length using demersal or pelagic gear to display two all-round white lights in a vertical line from where can best be seen with a nominal range of 1 mile when shooting their nets; one all-round white light over an all-round red light in a vertical line from where can best be seen with a nominal range of 1 mile when hauling their nets, and two all-round red lights in a vertical line from where can best be seen with a nominal range of 1 mile when their nets have come fast upon an obstruction.

When engaged in pair trawling at night, they should direct search lights at one another.

Vessels smaller than 20m are not required to obey these rules as they relate to trawlers, but may do so.

Purse seiners are also types of trawler. A vessel fishing with purse seine gear may exhibit two all-round yellow lights in a vertical line from where can best be seen with a nominal range of one mile; these lights flash alternately every second and with an equal light and occultation period. These lights may only be exhibited when the vessel is hampered by its gear and do not count as flashing lights as described under Rule 21 (f).

Trawlers, when stopped and making no way through the water, do not display either sidelights or a sternlight, but do once they start to make way. At anchor or when not underway, they are stopped and making no way. At anchor, then, they display no special lights or shapes to indicate that they are at anchor.

During the day, trawlers and fishing vessels that are not trawling display the same shapes, except when outlying gear exists.

 

(c)        A vessel engaged in fishing, other than trawling shall exhibit:

           

            (i)         two all-round lights in a vertical line, the upper being red and the lower white, or a shape consisting of two cones with apexes together in a vertical line one above the other;

            (ii)        when there is outlying gear extending more than 150m horizontally from the vessel, an all-round white light or a cone apex upwards in the direction of the gear;

            (iii)       when making way through the water, in addition to the lights prescribed in this paragraph, sidelights and a sternlight.

 

These rules are similar to the rules described in part (b) for trawlers, except that such vessels must not display a masthead light and so there is no indication of their size.

They show a red all-round light over a white all-round light in a vertical line, or two cones, apexes together. As with trawlers, there is no location on the vessel that these lights are required to be. As fishing vessels other than trawlers never display a masthead light, there is no reason why these lights should be forward, although convention places them there.

The red-over-white lights should not be confused with the lights for a vessel engaged in pilotage duty, which displays white-over-red lights. This is described in Rule 29. The lights for a vessel engaged in fishing other than trawling can be remembered by the phrase, ‘red over white, fisherman in sight’, and those for a pilot boat, ‘white over red, pilot ahead’.

Annex II does not apply to fishing vessels other than trawlers.

As with trawlers, when stopped and making not way through the water, fishing vessels other than trawlers display neither sidelights nor a sternlight.

The all-round white light or a cone apex upwards is placed in the direction of outlying gear extending more than 150m. This is to indicate that the vessel ought be passed on the side opposite to where the outlying gear extends. This should not be mistaken for a masthead light.

 

(d)       The additional signals described in annex II to these Regulations apply to a vessel engaged in fishing in close proximity to other vessels engaged in fishing.

 

The intensity, and therefore, the nominal range, of the lights described in annex II are not subject to the rules covered in Rule 22. Indeed, although they are effectively all-round lights, they have a nominal range of at least 1 mile, but otherwise must have a nominal range of less than that of any of the lights required to be shown by a fishing vessel.

Because, under Rule 22, the sidelights of a vessel of less than 12m have a nominal range of 1 mile, so too, if a trawler is required to and chooses to show the lights described in annex II, is the nominal range of the lights described in annex II. Larger vessels show lights of greater ranges, which means that the annex II lights may have a greater nominal range, but are not required to.

Trawling lights described in annex II must always be lower than the navigational lights described in this Rule.

 

(e)       A vessel when not engaged in fishing shall not exhibit the lights or shapes prescribed in this Rule, but only those prescribed for a vessel of her length.

 

This vessel is important, for a vessel must not be treated as a fishing vessel under the Rules, especially under Rules 9, 10 and 18 unless she is displaying the lights and shapes for a vessel engaged in fishing. Normally fishing vessels are power-driven vessels, but they may be sailing vessels, so they must display not only the lights and shapes for vessels of their length but also their type. They may also, when not considered to be fishing vessels, vessels affected by Rules 24, 26, 27, 28, 29 and 30. None of these rules apply when a vessel is engaged in fishing, but in theory any of the circumstances that would necessitate them to be complied with were they not engaged in fishing could apply to vessels engaged in fishing so that the manoeuvrability of the vessel is restricted.

 

 

A fishing vessel other than a trawler stopped and making no way through the water, may or may not be underway.

 

 

 

 

 

A fishing vessel other than a trawler underway and making way through the water, seen from the port side, with outlying gear extending more than 150m.

 

 

 

 

 

 

A trawler, maybe more than 50m in length although a smaller vessel may still display the masthead light which is displayed here, which is currently hauling its nets, stopped and making no way through the water, may or may not be underway.

 

 

 

 

 

A trawler, less than 50m in length, its nets come fast upon an obstruction, underway and making way, viewed from the port side

 

 

 

 

 

 

 

Rule 27

 

Vessels not under command or restricted in their ability to manoeuvre

 

(a)       A vessel not under command shall exhibit:

           

            (i)         two all-round lights in a vertical line where they can best be seen;

            (ii)        two balls or similar shapes in a vertical line where they can best be seen;

            (iii)       when making way through the water, in addition to the lights prescribed in this paragraph, sidelights and a sternlight.

 

A vessel not under command need not be a power-driven vessel under normal circumstances, but may be a sailing vessel.

The lights displayed by a vessel not under command are not in addition to any lights required under any other Rule. If a vessel is not under command, she is required to indicate that this is the case by exhibiting these lights and shapes and no others. A vessel not under command is a vessel that is not able to manoeuvre in compliance with the Rules, as defined by Rule 3 part (f). A vessel cannot be considered ‘propelled by machinery’ or ‘under sail’ if she cannot steer or move forward, and the loss of either of these functions means that such a vessel cannot be considered a power-driven vessel or a sailing vessel as defined by Rule 3 part (b) and (c).

A vessel not under command must display two all-round red lights in a vertical line, but if she is not making way, she is not obliged to show either sidelights or a sternlight. She never shows a masthead light or lights.

A vessel at anchor does have the capacity to manoeuvre, if she weighs anchor, and so is under command; however, a vessel at anchor may be not under command if she has lost this capacity. In this case, she shows the lights and shapes for a vessel not under command in addition to the lights and shapes for a vessel at anchor.

For a vessel less than 100m in length, the lights that the Rules require to be displayed are the same for a vessel aground as they are for a vessel not under command at anchor. Larger vessels at anchor are required to display all deck and working lights, and smaller vessels may do so, if they are at anchor; aground, they may not do so. Therefore, if a vessel is larger than 100m in length, it is possible to tell a vessel aground and a vessel not under command at anchor apart at night, and it may be possible if a smaller vessel chooses to show all available deck and working lights.

During the day, vessels not under command display two balls in a vertical line from where can best be seen. A vessel at anchor displays one ball in the fore part. A vessel aground displays, from where they can best be seen, three balls in a vertical line. Unless ‘where they can best be seen’ is the fore part of the vessel, the shapes displayed by vessels at anchor whilst not under command and vessels aground are different and it is possible to tell them apart.

Vessels not under command cannot tow other vessels; therefore, a vessel may display either the lights for a towing vessel, or a vessel not under command; not both.

 

A vessel not under command, and making no way through the water. May be made fast to the shore; otherwise, underway.

 

 

 

 

 

 

A vessel not under command, underway and making way, seen from the starboard side.

 

 

 

 

 

 

A vessel not under command at anchor. A vessel of less than 50m in length may display two all-round lights, but a vessel of more than 50m in length, shall. A vessel of less than 100m in length may show all available deck and working lights, but a vessel of more than 100m in length shall. Viewed from the starboard side.

 

 

 

 

 

A vessel of less than 50m in length, may be aground, or may be at anchor, not under command.

 

 

 

 

 

(b)       A vessel restricted in her ability to manoeuvre, except a vessel engaged in mine clearance operations, shall exhibit:

 

A vessel restricted in its ability to manoeuvre is so restricted because of the nature of its work. Potentially, a vessel could have a steering or engine breakdown during this time. In this situation, it becomes not under command; however, this may not affect the vessel if it is able to continue working, or it may affect the vessel in such a way as to prevent it from working; it may be able to continue working, and be restricted because of that, whilst also being restricted by engine or steering failure. Can such a vessel show both not under command lights and restricted in its ability to manoeuvre lights? Should it show one or the other?

If making way, a vessel not under command should not show masthead lights. Therefore, to do so would cause ambiguity; such a vessel might be mistaken for a vessel engaged in dredging or underwater operations (see part (d) of this Rule.) For this same reason, ambiguity could exist when stopped and not making way.

Although there is no specific rule forbidding it, because of the potential confusion that could arise from showing both lights at the same time, it should be avoided. Vessels not under command and vessels restricted in their ability to manoeuvre are treated, by other vessels, the same under the Rules, as explained in Rule 18; therefore, it does not matter which is shown.

The definition of a vessel restricted in its ability to manoeuvre is at Rule 3, part (g), and includes specifically vessels laying, servicing, or picking up navigation marks, submarine cables or pipelines, engaged in dredging, surveying, or underwater operations, engaged in replenishment or transferring persons, provisions or cargo while underway, engaged in the launch or recovery of aircraft, engaged in mineclearance operations, and engaged in towing where the tow and towing vessel are severely restricted in their ability to deviate from their course, and may include any other type of vessel which, due to the nature of her work, is unable to manoeuvre as required by the Rules.

Note that fishing vessels, despite being defined as vessels with restricted manoeuvrability, are not classed as vessels restricted in their ability to manoeuvre.

This rule may apply to either sailing or power-driven vessels, although it is usually considered to apply to power-driven vessels. Note that vessels restricted in their ability to manoeuvre need not be underway.

Normally, when at anchor, part (iv) of this part applies, and when stopped and making no way though the water, only part (i) and (ii) of this part applies. However, a vessel engaged in dredging or underwater operations does not obey this part, but part (d), and does not indicate that it is at anchor. If no obstruction exists, it displays only the red, white, and red lights at night and ball, diamond and ball shapes during the day, if not making way, whether or not it is at anchor. Because of this, confusion exists; when not making way, a vessel restricted in its ability to manoeuvre may or may not be underway; there is no way to tell.

 

            (i)         three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle shall be white;

            (ii)        three shapes in a vertical line where they can best be seen. The highest and lowest of these shapes shall be balls and the middle one a diamond;

            (iii)       when making way through the water, a masthead light or lights, sidelights and a sternlight, in addition to the lights prescribed in subparagraph (i);

 

This rule makes it quite clear that the authors of the IRPCS were thinking that only a power-driven vessel would ever be considered restricted in its ability to manoeuvre, as this rule states that when making way, it looks like a power-driven vessel that is also displaying its RAM lights.

However, nothing in the Rules prevents a sailing vessel from being restricted in its ability to manoeuvre. The phrasing of this Rule seems to indicate, by saying ‘a masthead light or lights,’ that if the vessel restricted in its ability to manoeuvre is greater than 50m in length, it should show a second masthead light abaft of and higher than the forward one; however, this is not strictly stated. It should be assumed that this is the intention, as there is no other guidance as to the placement and number of masthead lights required.

Note that when stopped, the vessel restricted in its ability to manoeuvre displays only the red, white, and red all-round lights in a vertical line. Because this rule gives clear instructions that sidelights, the sternlight, and masthead lights are not to be shown unless the vessel is making way, it should be assumed that the lights described in this Rule are instead of, as opposed to being in addition to, the lights that are required to be shown for a vessel of its type.

 

            (iv)       when at anchor, in addition to the lights or shapes prescribed in subparagraphs (i) and (ii), the light, lights or shape prescribed in Rule 30.

 

Note that this means in addition to whatever lights or shape must be shown for a vessel at anchor, it also means only the red-white-red lights or ball-diamond-ball shapes are shown. Despite any similarities between vessels aground and vessels at anchor, vessels aground cannot also be restricted in their ability to manoeuvre and cannot display these lights or shapes as well.

 

A vessel restricted in its ability to manoeuvre, stopped and making no way through the water, may or may not be underway.

 

 

 

 

 

 

A vessel restricted in its ability to manoeuvre, a vessel of less than 50m in length may display such lights but a vessel of more than 50m in length must do, underway and making way, seen from the port side.

 

 

 

 

 

 

A vessel restricted in her ability to manoeuvre, at anchor, seen from the port side, less than 100m in length, vessel more than 50m must but a vessel less than 50m in length may show these lights.

 

 

 

 

(c)        A power-driven vessel engaged in a towing operation such as severely restricts the towing vessel and her tow in their ability to deviate from their course shall, in addition to the lights or shapes prescribed in Rule 24(a), exhibit the lights and shapes prescribed in subparagraphs (b)(i) and (ii) of this Rule.

 

This is a special rule for vessels restricted in their ability to manoeuvre. Although a vessel so restricted is required to show that she is, a towing vessel is also. A vessel cannot tow if she is not under command, but she can if it is the towing that is causing her to be restricted in her ability to manoeuvre.

Towing vessels display towing lights in addition to the lights they display for power-driven vessels, with exceptions described under Rule 24. Rule 24 does not apply to sailing vessels, hence neither does this Rule. The lights in this Rule are similarly in addition to the lights for a power-driven vessel, unlike part (b), which are instead of the lights displayed by a power-driven vessel.

Note that not all towing vessels are restricted in their ability to manoeuvre.

 

A towing vessel, a vessel less than 50m in length may but a vessel more than 50m in length must show these lights, towing an object more than 200m in length, restricted in its ability to manoeuvre, seen from the port side.

 

 

 

 

 

 

(d)       A vessel engaged in dredging or underwater operations, when restricted in her ability to manoeuvre, shall exhibit the lights and shapes prescribed in subparagraphs (b)(i), (ii) and (iii) of this Rule and shall in addition, when an obstruction exists, exhibit:

 

Note that (b)(iv) is not included, because of part (iii) of this part. If a vessel is engaged in dredging or underwater operations without causing an obstruction, parts (i) and (ii) of this part do not apply.

 

            (i)         two all-round red lights or two balls in a vertical line to indicated the side on which the obstruction exists;

            (ii)        two all-round green lights or two diamonds in a vertical line to indicate the side on which another vessel may pass;

 

Typically, these lights will be exhibited from either end of the foreyard, but there is no requirement for this under the Rules. When stopped and making no way through the water, a vessel engaged in dredging or underwater operations shows no aspect, and therefore it is impossible to judge whether or not an obstruction exists on the vessel’s port or starboard side. These lights do, however, indicated to the observer which side it is safe to pass on.

 

            (iii)       when at anchor, the lights or shapes prescribed in this paragraph instead of the lights or shape prescribed in Rule 30.

 

It should be noted that a vessel engaged in dredging or underwater operations displays no indication that it is at anchor whatsoever. Since part (b)(iii) of this Rule applies, however, when at anchor, it does not display sidelights nor a sternlight, nor any masthead lights. Because of this, it can be can be identified as underway when making way, but not identified as being underway (or not) when it is stopped.

 

A vessel engaged in dredging or underwater operations, stopped and making no way through the water, may or may not be underway, an obstruction exists on the viewer’s starboard side; it is safe to pass on the viewer’s port side.

 

 

 

 

 

A vessel engaged in dredging or underwater operations, underway and making way, a vessel more than 50m in length must show these lights but a vessel of less than 50m in length may show them, seen from right ahead, and obstruction exists on the vessel’s starboard side, it is safe to pass on the vessel’s port side.

 

 

 

 

(e)       Whenever the size of a vessel engaged in diving operations makes it impracticable to exhibit all lights and shapes prescribed in paragraph (d) of this Rule, the following shall be exhibited:

 

Part (g) of this rule makes specific mention of diving vessels, stating that vessels of less than 12m in length are not required to follow this Rule. Presumably, then, a vessel must obey this Rule when she is 12m in length, and obey part (d) when greater than.

           

            (i)         three all-round lights in a vertical line where they can best be seen. The highest and lowest of these lights shall be red and the middle light shall be white;

 

Again, a vessel showing these lights is definitely restricted in her ability to manoeuvre, but she cannot be judged to be underway or not, and in this case, she may be making way.

A vessel of this size is not required to show the lights and shapes required in part (d), but this does not mean that she is not bound to follow part (d) entirely; part (d)(iii) requires, when she is at anchor, that she does not show the lights for vessels at anchor. Because she does not show the lights and shapes required by part (d), she follows those for part (e) instead.

 

            (ii)        a rigid replica of the International Code flag “A” not less than 1m in height. Measures shall be taken to ensure its all-round visibility.

 

A flat, rigid, 1m high copy of the alpha flag is a flat object and not visible from every angle. It can therefore be assumed that several images of the alpha flag should be shown; at least three, perhaps four. Alternatively, the replica could rotate.

 

A copy of the International Code of Signals flag, “A”, or Alpha.

 

 

 

 

 

 

(f)         A vessel engaged in mine clearance operations shall in addition to the lights prescribed for a power-driven vessel in Rule 23 or to the lights or shape prescribed for a vessel at anchor in Rule 30 as appropriate, exhibit three all-round green lights or three balls. One of these lights or shapes shall be exhibited near the foremast head and one at each end of the fore yard. These lights or shapes indicate that it is dangerous for another vessel t approach within 1000m of the mine clearance vessel.

 

Part (b) specifically precludes vessels engaged in mineclearance operations. Only this rule applies. Only power-driven vessels need show these lights or shapes, and only they may be considered mineclearance vessels. Note that these vessels are considered restricted in their ability to manoeuvre, although they do not show the red, white and red all-round lights typical of other sorts of vessels restricted in their ability to manoeuvre.

These lights and shapes are in addition to the lights and shapes for a power-driven vessel, unlike in part (b), in which the lights are shown instead of the lights for a vessel of her type. A vessel engaged in mineclearance operations may be at anchor, in which case these lights are again shown in addition to the lights required by Rule 30.

 

A vessel engaged in mineclearance operations less than 50m in length underway, may or may not be making way, viewed from right forward.

 

 

 

 

 

 

A vessel engaged in mineclearance operations, a vessel less than 50m may, but a vessel greater than 50m in length must show these lights; less than 100m in length, at anchor, viewed from the starboard side.

 

 

 

 

 

 

 

A vessel engaged in mineclearance operations, a vessel less than 50m in length may, but a vessel of greater than 50m in length must show these lights; underway, may or may not be making way, as viewed from the starboard side.

 

 

 

 

 

(g)       Vessels of less than 12m in length, except those engaged in diving operations, shall not be required to exhibit the lights and shapes prescribed in this Rule.

 

This means that vessels smaller than 12m in length engaged in mineclearance operations are not required to inform others of this fact! This may not, realistically, be an issue.

This part of this Rule does not say that smaller vessels may display the lights and shapes required by this Rule; therefore, it may be assumed that vessels smaller than 12m in length should not show them, even if not under command or restricted in ability to manoeuvre. The exception to this is for vessels engaged in diving activities, which, if less than 12m in length, follow part (e) of this Rule and part (d), by extension.

Vessels of this size follow the Rules for vessels of their type and size, that is, as prescribed under Rules 23 or 25.

 

(h)        The signals prescribed in this Rule are not signals of vessels in distress and requiring assistance. Such signals are contained in annex IV to these Regulations.

 

Rule 28

 

Vessels constrained by their draught

 

A vessel constrained by her draught may, in addition to the lights prescribed for power-driven vessels in Rule 23, exhibit where they can best be seen three all-round red lights in a vertical line, or a cylinder.

 

Unlike many other similar rules, vessels constrained by their draught are not required to show these lights or this shape, but may do so. In doing so, they indicate that their passage or safe passage is not to be impeded, as mentioned in  Rule 18 part (d).

Vessels the passage or safe passage of which are not to be impeded are not unable to manoeuvre as required by the Rules, being neither not under command nor restricted in their ability to manoeuvre, and therefore, although their navigational options are impeded by the fact that they are following a narrow channel, are still considered able to obey the requirements of the Rules and take action to avoid a collision; such action will more likely consist of an alteration of speed than of course.

Other vessels are required not to avoid impeding the passage or safe passage of a vessel constrained by her draught, except for vessels not under command or restricted in their ability to manoeuvre, but they are not directed to keep clear as they would for, for example, a vessel not under command. This may amount to the same thing in many circumstances, but when there are no other safe options and a risk of collision exists with a vessel constrained by her draught, such a vessel shall be treated as a normal power-driven vessel, in which case, she is required to take avoiding action.

An example of this is if she is following a dredged channel, surrounded by fishing vessels. A power-driven vessel of a lesser draught is crossing her path from her starboard side. The vessel of lesser draught cannot alter course, nor lessen her speed whilst keeping clear of the fishing vessels, so she acts as a stand-on vessel, making the vessel constrained by her draught the give-way vessel. The give-way vessel must then reduce her speed to avoid a collision.

Only power-driven vessels can be considered vessels constrained by their draught. They must show the three red lights in a vertical line from where can best be seen, or a cylinder, in addition to those required for a power-driven vessel. This means that vessels towing, pushing or towing alongside can be considered constrained by their draughts, as can vessels engaged in mineclearance operations (see Rules 24 and 27 part (f)).

Towing vessels can indicate that they are constrained by their draught and restricted in their ability to manoeuvre. However, the fact that other vessels are required to keep clear of a vessel restricted in its ability to manoeuvre makes requiring them to avoid impeding her superfluous, so a towing vessel should not show both lights, so as to minimise the chances of confusion.

 

A towing vessel, less than 50m in length, constrained by her draught, length of tow more than 200m, seen from the port side.

 

 

 

 

 

 

A power-driven vessel constrained by her draught, a vessel of less than 50m in length may, but a vessel of greater than 50m in length must show these lights, as seen from the starboard side.

 

 

 

 

 

 

 

Rule 29

 

Pilot vessels

 

(a)       A vessel engaged on pilotage duty shall exhibit:

 

            (i)         at or near the masthead, two all-round lights in a vertical line, the upper being white and the lower red;

 

The popular saying, ‘white over red, pilot ahead’ can be used to remember this configuration of lights. It should not be confused with the lights for a fishing vessel other than a trawler, which displays one red over one white light; that can be remembered as, ‘red over white, fisherman in sight.'

These lights are displayed from the masthead, from where can best be seen. This is not necessarily at the forward end of the vessel; pilot boats display no other masthead lights when on duty, and since there is no requirement to show any second masthead lights abaft of and higher than the forward one, she may display these lights closer to the stern of the vessel.

Note that these lights are shown from the masthead but are not masthead lights, but all-round lights.

 

            (ii)        when underway, in addition, sidelights and a sternlight;

            (iii)       when at anchor, in addition to the lights prescribed in subparagraph (i), the light, lights or shape prescribed in Rule 30 for vessels at anchor.

 

These lights are to be displayed instead of, not in addition to, the lights displayed for a vessel of its type, and a vessel need not be power-driven to be considered a pilot boat. Vessels at anchor that are on pilotage duty display the pilot lights in addition to the anchoring light or lights; this is an exception to the rule. The anchoring light will usually be one all-round white light where can best be seen for few pilot boats will be as large as 50m in length. This does not include vessels aground; they are not vessels at anchor, and may not display pilot lights.

Note that sidelights and a sternlight are exhibited when the pilot boat is underway, not making way. Since at anchor she shows her anchoring light(s) and when aground she cannot show pilot lights, a vessel displaying only a white all-round light over a red all-round light can only be moored. Like power-driven vessels, there is no way to distinguish a pilot boat making way from one stopped and making no way through the water.

Because vessels on pilotage duty do not comply with Rule 23 or 25, they cannot be considered towing vessels, vessels constrained by their draught, or mineclearance vessels, or any other type of vessel that shows its own lights and shapes instead of those described in Rules 23 and 25 for power-driven and sailing vessels.

 

(b)       A pilot vessel when not engaged on pilotage duty shall exhibit the lights or shapes prescribed for a similar vessel of her length.

 

This Rule makes it clear that sailing vessels (or vessels under oar lit as sailing vessels) are not exempt from being considered pilot vessels.

 

A vessel engaged on pilotage duty, seen from right forward, underway, may or may not be making way.

 

 

 

 

 

 

A vessel engaged on pilotage duty at anchor, seen from either right astern or right forward, less than 50m in length.

 

 

 

 

 

 

 

Rule 30

 

Anchored vessels and vessels aground

 

Vessels at anchor or aground are not considered underway, as define by Rule 3 part (i). Rules 23 and 25 described the lights to be shown by power-driven and sailing vessels respectively, but only when underway. Therefore, both obey this Rule when aground or at anchor; vessels at anchor are not to be considered neither power-driven nor sailing vessels for the purposes of the Rules.

The lights and shapes to be displayed by vessels at anchor or aground are instead of, as opposed to in addition to, the lights required elsewhere, except where it has been explicitly stated.

Vessels at anchor may be considered fishing vessels, but if they do, they do not obey this Rule, but only show the lights and shapes dictated by Rule 26.

Vessels at anchor are not explicitly allowed to also be considered vessels not under command, but there is nothing in the Rules which disallows it, and vessels are required to indicate that they are not under command or at anchor by their lights and shapes, so it should be assumed that both lights and shapes can be shown according to each rule. This is described in Rule 27 part (a).

Vessels restricted in their ability to manoeuvre are explicitly required to show appropriate lights and shapes, as described in Rule 27 part (b), in addition to those they show at anchor.

A vessel cannot tow at anchor. Vessels engaged in dredging or underwater operations at anchor do not comply with this Rule, but instead comply with Rule 27 part (d) and (e). Mine clearance vessels exhibit the lights and shapes described in Rule 27 part (f) in addition to those at anchor.

Vessels may not be considered constrained by their draught at anchor. Pilot vessels at anchor show pilot lights in addition to those they show at anchor, as described in Rule 29.

There is no Rule that specifically states other vessels must avoid or keep clear of vessels at anchor, although obviously such vessels are unable to avoid or keep clear of oncoming traffic. The reason for this is that such vessels are perfectly manoeuvrable, unlike vessels not under command, for example. Rule 18, which describes the responsibilities between vessels, requires power-driven vessels and sailing vessels to keep out of the way or avoid impeding other types of vessels. Because at anchor vessels are not underway and do not display the lights and shapes for power-driven vessels or sailing vessels, it is possible to interpret that such vessels are not considered vessels of those types and therefore are under no obligation to keep clear of or avoid impeding any other sort of vessel.

Without this interpretation, they are still at anchor and under Rule 2, which requires an officer of the watch to take precautions required by the ordinary practice of seamen, and such a set of precautions should include keeping clear of vessels at anchor.

 

(a)       A vessel at anchor shall exhibit where it can best be seen:

            (i)         in the fore part, an all-round white light or one ball;

            (ii)        at or near the stern and at a lower level than the light prescribed in subparagraph (i), an all-round white light.

 

(b)       A vessel of less than 50m in length may exhibit and all-round white light where it can best be seen instead of the lights prescribed in paragraph (a) of this Rule.

 

(c)        A vessel at anchor may, and a vessel of 100m and more in length, shall also use the available working or equivalent lights to illuminate her decks.

 

Vessels of less than 50m in length are not obliged to display one all-round white light, nor a vessels less than 100m obliged to refrain from displaying her deck or working lights. A vessel showing only one all-round white light at anchor must be less than 50m in length but she may also show her working lights, and a vessel showing two anchor lights may be less than fifty metres in length; if showing working lights, she may be of any length. A vessel must show her deck lights if more than 100m and show two all-round white lights if more than 50m in length.

Note that a single white light can mean many things under the Rules; it may just as easily be the stern light of any vessel not displaying any all-round lights. It could also be the all-round light of a power-driven vessel less than 7m in length, or the single masthead light of a power-driven vessel viewed from outside the nominal range of her sidelights. A single white light could also belong to a vessel aground of less than 12m, which is not obliged to indicate that is aground as opposed to at anchor; this is described in part (f) of this Rule.

Caution should be taken against confusing these requirements with those in Rule 35, which governs sound signals in restricted visibility. Vessels more than 100m in length must ring a bell in the fore part and then ring a gong in the after part. This should be, if anything, equated with the requirement of vessels to display their deck and working lights at anchor if the vessel is more than 100m in length, as opposed to the requirement that they show two all-round lights if greater than 50m in length.

Remember that these Rules apply in all weathers, including restricted visibility; during the day, the lights should be displayed in restricted visibility as it makes the vessel visible at a greater range.

 

(d)       A vessel aground shall exhibit the lights prescribed in paragraph (a) or (b) of this Rule and in addition, where they can best be seen:

 

            (i)         two all-round red lights in a vertical line;

            (ii)        three balls in a vertical line.

 

As has been mentioned in the notes for vessels not under command in Rule 27 part (a), vessels aground, at night, show the same lights as vessels not under command at anchor. The exception to this is that vessels aground never show their deck or working lights. During the day, vessels not under command show only two balls from where can best be seen, in addition to the one ball in the fore part for a vessel at anchor, but vessels aground show three balls from where can best be seen, in addition to one ball in the fore part.

Vessels aground of less than 50m in length may show only one all-round light instead of two, one forward and one aft, just as vessel at anchor may.

Remember that in restricted visibility, a gong is sounded in the after part of a vessel aground if the vessel is more than 100m in length. (This is mentioned in Rule 35.) Remember this because vessels aground do not show deck or working lights, even if they are over 100m in length, as anchored vessels do; but they do sound a gong in the after part of the vessel if greater than 100m in length.

 

(e)       A vessel of less than 7m in length, when at anchor, not in or near a narrow channel, fairway or anchorage, or where other vessels normally navigate, shall not be required to exhibit the lights or shape prescribed in paragraphs (a) and (b) of this Rule.

 

Vessels should avoid anchoring in a narrow channel or fairway anyway. This exemption from the need to comply with the Rules regarding anchoring only applies in places where other vessels normally do not navigate; it is not a general exemption. Also, this exemption does not apply to vessels aground; vessels aground of less than 12m in length are so exempted from complying with part (d) in part (f) of this Rule.

 

(f)         A vessel of less than 12m in length, when aground, shall not be required to exhibit the lights or shapes prescribed in subparagraphs (d)(i) and (ii) of this Rule.

 

Note that this exemption does not exempt such vessels from the need to display the same lights as a vessel at anchor when she is aground and less than 12m in length; such vessels must display at least one all-round white light, or two if they so choose, but even though they do not display two all-round red lights in a vertical line or three balls, they may not show any deck or working lights, as a vessel at anchor may.

Also note that part (e) of this Rule, which exempts vessels of less than 7m in length from the need to comply with the Rules regarding anchoring under certain circumstances, does not exempt vessels of less than 7m from the need to comply with thus Rule, which does not relate at all to anchoring, but to vessels aground. Such vessels must show at least one white all-round light if aground.

 

A vessel aground, more than 50m in length, seen from the port side.

 

 

 

 

 

A vessel at anchor, less than 50m in length, showing deck and working lights, this one seen from the starboard side.

 

 

 

 

 

 

Rule 31

 

Seaplanes and WIG craft

 

Where it is impracticable for a seaplane or a WIG craft to exhibit lights and shapes of the characteristics or in the positions prescribed in the Rules of this Part she shall exhibit lights and shapes as closely similar in characteristics and position as is possible.

 

This Rule is in some regards similar to Rule 1, part (e), except that this Rule specifically governs the aforementioned WIG craft and seaplanes. Chiefly, no government intervention or approval is required, although doubtless regulations exist governing the sound design of aircraft and/or WIG craft.

 

PART D – SOUND AND LIGHT SIGNALS

 

Rule 32

 

Definitions

 

(a)       The word whistle means any sound signalling appliance capable of producing the prescribed blasts and which complies with the specifications in annex III to these Regulations.

 

Annex III describes the qualities required by all sound signalling appliances on board a vessel. Much of this is technical information, and the gross physical quantities of the appliances involved, and will be of more concerned to the shipbuilder than the mariner, as seamen have no means of measuring audibility.

Of note, the audibility of sound signalling appliances is described. Vessels of 200m or more must be audible for 2 miles; 75m or more, 1.5 miles; 20m or more, 1 mile, and vessels smaller than 20m in length must be audible for 0.5 miles.

These nominal ranges are important, because it greatly informs what should be the ‘safe speed’ of a vessel, in reference to Rule 6. In addition, if it is clearly visible that there are no vessels within the nominal range of the sound-signalling appliances, there logically need be no legal obligation to make a sound signal, and to make sound signals ‘just in case’ indicates poor situational awareness.

 

(b)       The term short blast means a blast of about one second’s duration.

 

(c)        The term prolonged blast means a blast of from four to six second’s duration.

 

Rule 33

 

Equipment for sound signals

 

This Rule dictates the requirements as to which types of sound signalling appliances are required on vessels of certain length. Note that there is no differentiation between power-driven vessels or sailing vessels. This Rule may be compared to Rules 21 and 22, which describe the different types of lights and their visibility and nominal ranges. Annex III contains the gross physical qualities required of these appliances.

 

(a)       A vessel of 12m or more in length shall be provided with a whistle, a vessel of 20m or more in length shall be provided with a bell in addition to a whistle, and a vessel of 100m or more in length shall, in addition, be provided with a gong, the tone and sound of which cannot be confused with that of the bell. The whistle, bell and gong shall comply with the specification in annex III to these regulations. The bell or gong or both may be replaced by other equipment having the same respective sound characteristics, provided that manual sounding of the required signals shall always be possible.

 

(b)       A vessel of less than 12m in length shall not be obliged to carry the sound signalling appliances prescribed in paragraph (a) of this Rule but if she does not, she shall be provided with some other means of making an efficient sound signal.

 

Rule 34

 

Manoeuvring and warning signals

 

Parts (a), (c) and (d) only apply to vessels in sight of one another. Part (b) covers lights signals, which are only sounded in addition to sound signals, and therefore only when vessels are in sight of one another. Part (f) regards the use of whistles if more than one whistle is fitted. Only part (e) of this Rule applies both inside and outside of restricted visibility. Therefore, it is prudent to think of Rule 34 as describing sound signals that apply when two vessels are in sight of one another, and think of part (e) of this Rule as a small exception.

 

(a)       When vessels are in sight of one another, a power-driven vessel underway, when manoeuvring as authorised or required by these Rules, shall indicate that a manoeuvre by the following signals on her whistle:

           

-           one short blast to mean “I am altering my course to starboard”;

-           two short blasts to mean “I am altering my course to port”;

            -           three short blasts to mean “I am operating astern propulsion”.

 

Readers familiar with the International Code of Signals will know that the flags, “E”, “I” and “S”, or “ECHO”, “INDIA” and “SIERRA”, mean, “I am altering my course to starboard,” “I am altering my course to port,” and “I am operating astern propulsion,” respectively. The Morse Code for these signals is  , ▪▪ and  ▪▪▪ respectively. Therefore, this particular part of this Rule is very easy to remember indeed.

It is very important to remember to make these sound signals when making any alteration of course outside of restricted visibility, and to remember not to make these sound signals when in conditions of restricted visibility. However, when it is clear that there are no vessels within the nominal range of your vessel’s sound signalling appliances, there is no legal obligation to make such sound signals.

Rule 8 parts (a), (b) and (c) make it clear that alterations of course made to avoid a collision should be sufficient that they can be easily observed from another vessel. This part of this Rule states that manoeuvres authorised or required by these Rules should be accompanied by an appropriate sound signal described here. Strictly speaking, these Rules do not authorise alterations of course (or the use of astern propulsion) for navigational purposes, when no risk of collision or possibility of impeding another vessel’s passage is involved. In addition, these manoeuvres are not required to be bold, ‘in ample time’ or visible to another vessel observing visually or by radar. However, it is in the best interest of the navigator to inform other vessels of when ones vessel is to soon make a bold alteration of course or operate astern propulsion, especially since when other vessels are within the nominal range of ones ship’s whistle, a ‘close-quarters situation’ may be deemed to exist. Therefore, sound signals should be made regardless of whether or not they are authorised by the Rules.

Note that three short blasts on the ship’s whistle is for use when a vessel is about to operate astern propulsion, not simply when moving astern, or slowing down; and indeed when operating astern propulsion, this sound signal should be made, even when moving ahead.

There is some debate as to whether tugs assisting vessels under pilotage leaving or entering their berth under the direction of the pilot need make these sound signals. The consensus is, generally, that they need not make these sound signals, although some do. Strict interpretation of the Rules would suggest that they do, in which case they should comply with Rule 24, which governs towing and pushing vessels and vessels being towed or pushed ahead. There are many complications to this, however, because several tugs may be in use, from several angles, some pushing, some towing, some towing backwards, and so forth. Special Rules made by appropriate authorities for harbours, as described in Rule 1 part (b), trump the IRPCS, although they should resemble it; this may include a suspension of these Rules (and Rule 24) for tugs assisting in the pilotage of a vessel to or from a berth.

It is essential to not that this Rule applies only to power-driven vessels. It does not apply to sailing vessels. Vessels not underway do not necessarily count as either power-driven vessels nor sailing vessels (although this may not be interpreted as being the case universally) but vessels not underway generally do not manoeuvre.

 

(b)       Any vessel may supplement the whistle signals prescribed in paragraph (a) of this Rule by light signals, repeated as appropriate, whilst the manoeuvre is being carried out:

           

These signals should only ever be made in addition to the sound signals, not instead of. Part (iii) of this part states that the nominal range of this light shall be 5 miles, which exceeds the maximum nominal range of the sound-signalling appliances. No vessel is required to make these signals, but it is safer to do so in order to inform other vessels of your movements.

Remember that if another vessel is within a range below the nominal range of the vessel’s sound signals, a vessel is legally required to make the sound signals; above that, she is not, so she is not bound to make sound signals that are required to be made before making lights signals, but she must make the sound signals before she makes the light signals, even if nobody is within range of the sound signals to hear them. Remember that often (more likely, usually) the actual range of lights and sound signals exceeds the nominal range, and more signals made means less of a risk of collision, as all parties are more informed.

 

            (i)         these light signals shall have the following significance:

 

            -           one flash to mean “I am altering my course to starboard”;

            -           two flashes to mean “I am altering my course to port”;

            -           three flashes to mean “I am operating astern propulsion”;

 

The notes for part (a) of this Rule described how best to remember these; the signals, in the Morse Code, are the same as for the sound signals.

 

            (ii)        the duration of each flash shall be about one second, the interval between flashes shall be about one second, and the interval between successive signals shall not be less than ten seconds;

 

This part may be compared with Rule 32 which describes the length of short blasts on the ship’s whistle, among other things.

 

            (iii)       the light used for this signal shall, if fitted, be an all-round white light, visible at a minimum range of 5 miles, and shall comply with the provisions of annex I to these Regulations.

 

Note that the signalling light described here is not mention in Rule 22, which describes the visibility of lights; it is not a ‘navigational light’, nor a searchlight, which is directional, and the range of 5 miles is the same for all vessels. If this seems excessive for, for example, small yachts and rowing boats, it should be recalled that it is not required of any vessel to make the light signals described in part (b) of this part, and hence not required of vessels to be equipped with such a light.

 

(c)        When in sight of one another in a narrow channel or fairway:

 

This Rule specifically applies with Rule 9 part (e), which covers the conduct of vessels in a narrow channel or fairway, specifically when one vessel, intending to overtake another, requires the other vessel to move out of the way to permit safe passage. This Rule, and Rule 9 part (e), do not apply when overtaking in general, or when overtaking in a narrow channel when the other vessel need take no action to permit safe passing.

 

            (i)         a vessel intending to overtake another shall in compliance with Rule 9 (e) (i)   indicate her intention by the following signals on her whistle:

 

            -           two prolonged blasts followed by one short blast to mean “I intend to overtake you on your starboard side”;

            -           two prolonged blasts followed by two short blasts to mean “I intend to overtake you on your port side”.

 

This part of this part of this Rule can be remember as the signal “MIKE” in the Morse Code, that is, two prolonged blasts, ▬ , followed by the signal “ECHO” in the Morse Code, that is, one short blast, ▪, for when a vessel is to be overtaken on the starboard side (which can be remembered, as is the case in part (a) of this Rule, by the equivalent flag,) or followed by the signal “INDIA” in the Morse Code, that is, two short blasts, ▪▪, for when a vessel is to be overtaken on the port side (which can be remembered, as is the case in part (a) of this Rule, by the equivalent flag.)

 

            (ii)        the vessel about to be overtaken when acting in accordance with Rule 9 (e) (i) shall indicate her agreement by the following signal on her whistle:

 

            -           one prolonged, one short, one prolonged and one short blast, in that order.

 

This part of this part of this Rule can be remember as the signal “CHARLIE” in the Morse Code, that is, one prolonged, one short, one prolonged and one short blast, ▬▪▬▪. In the International Code of Signals, the flag “C” for “CHARLIE” means, “Yes”, or, the significance of the previous signal should be read in the affirmative. This Rule is therefore easy to remember; the overtaking vessel signals, ‘may I pass on the left?’ or ‘may I pass on the right?’ and then the vessel replies, ‘yes,’ if he intends to take action to permit safe passage.

There is no, ‘no,’ response in this part of this Rule. A vessel not intending to take action is under no obligation to make any sound signal in response, in which case, the vessel intending to overtake should not attempt to do so; however, vessels may choose to respond by making the sound (and possibly the accompanying light) signal described below in part (d) of this Rule, which means, ‘I fail to understand your intentions,’ or, ‘I doubt whether you are taking sufficient action to avoid collision.’ This is specifically mentioned in Rule 9 (e) (i).

It does not specifically state that vessels are allowed to make light signals instead of, or to accompany these sound signals. Therefore, vessels are forbidden from doing so. Since the overtaking vessel is behind the other, the vessel to be overtaken is less likely to notice a light signal, anyway.

It is stated in Rule 9 that sailing vessels are forbidden from impeding the passage of a vessel that can safely navigate only within a narrow channel, and in general, power-driven vessels are to keep clear from sailing vessels. However, sailing vessels may overtake one another, and power-driven vessels, and follow the Rules for overtaking vessels in Rules 9, 13, and 34. A sailing vessel may make the signals described in this Rule, in order to ‘ask’ another vessel to move out of her path. This is specifically allowed under Rule 13.

 

(d)       When vessels in sight of one another are approaching each other and from any cause either vessel fails to understand the intentions or actions of the other, or is in doubt whether sufficient action is being taken by the other to avoid collision, the vessel in doubt shall immediately indicate such doubt by giving at least five short and rapid blasts on the whistle. Such signal may be supplement by a light signal of at least five short and rapid flashes.

 

This signal is mentioned in Rule 9(e)(ii), but it may be used in any circumstance when deemed necessary, especially when your vessel is a stand-on vessel and the other directed to give way, but is not doing so.

The light signal must be made in addition to the sound signal, not instead of. This signal may not be used in restricted visibility. Note that light signals made during the day are very unlikely to be noticed.

A vessel may make a minimum of five short and rapid blasts on the ship’s whistle, but she may make any number, so long as they are short and rapid. The minimum, that is, five short and rapid blasts, can be remembered as “5” in the Morse Code, that is, five short blasts, ▪▪▪▪▪.

 

(e)       A vessel near a bend or an area of a channel or fairway where other vessels may be obscured by an intervening obstruction shall sound one prolonged blast. Such signal shall be answered within hearing around the bend or behind the intervening obstruction.

 

This part of this Rule does not apply when vessels are in sight of one another (what would be the point otherwise?) This is an exception; the rest of this Rule applies to vessels in sight of one another. It also, then, applies in conditions of restricted visibility, whereas the rest of the parts of this Rule do not. It does not, however, apply solely in restricted visibility.

Because this Rule applies only when another vessel might be obscured by some object or other, no light signals may accompany these sound signals.

Both vessels, whether calling or reply, make the same sound signal; this sound signal can be remembered as “TANGO” in the Morse Code, that is, one prolonged blast on the ship’s whistle, ▬.

Because any and all vessels approaching a bend or intersection of a channel make this signal, it can be assumed that the vessel that makes the signal first will ‘get there’ first, or in other words, is nearer. Common sense therefore dictates that they should have ‘right of way’, allowing the other vessel to slow down and navigate with caution knowing that a close-quarters situation in a narrow channel may be approaching. The appropriate course of action will vary with the situation and is not covered by the Rules specifically, although knowing, and taking, the correct course of action is considered part of the ‘ordinary practice of seamen’ and is therefore required under Rule 2.

 

(f)         If whistles are fitted on a vessel at a distance apart of more than 100m, one whistle only shall be used for giving manoeuvring and warning signals.

 

‘Manoeuvring and warning signals’ means only the signals described in this part. It does not say which of the two whistles shall be used.

 

Rule 35

 

Sound signals in restricted visibility

 

In or near an area of restricted visibility, whether by day or night, the signals prescribed in this Rule shall be used as follows:

 

Note that automatic sound signalling should commence before entry into a fog bank (or other similar area of restricted visibility). A vessel inside an area of restricted visibility will be unable to view a vessel outside it, so that it is important for a vessel not in an area of restricted visibility but near it to make sound signals so that a vessel within the area can detect the other by sound.

 

(a)       A power-driven vessel making way through the water shall sound at intervals of not more than 2 minutes one prolonged blast.

 

Note that a power-driven vessel when making way can make sound signals more frequently than once every two minutes. Consider the vessel’s speed when determining the amount of time between sound signals; if a vessel is travelling at 15 knots, she will travel half a mile between prolonged blasts if signalling only once every two minutes. A vessel of less than 75m in length is required to have a whistle with an audible range of only one mile; thus, if two such vessels were approaching at that speed at a reciprocal course, they would have no time in which to detect each other and thus avoid collision if conditions were such that they are only able to detect each other by hearing one another’s sound signal. Of course, in this example, 15 knots cannot be considered a ‘safe speed’ but it is always safer to reduce the amount of time between prolonged blasts on the ship’s whistle.

In principle, a vessel could simply produce one prolonged blast after the other as their sound signal in restricted visibility. This could cause confusion with a power-driven vessel stopped and making no way through the water, but not with any other type of vessel, and also, not with a vessel in distress (a vessel in distress can indicate such by making a continuous sounding with any fog-signalling apparatus). It can be assumed that to avoid confusion with a vessel making the signals for a power-driven vessel stopped and making no way through the water, a power-driven vessel when making way should probably allow at least ten seconds duration between single prolonged blasts, and common sense dictates that probably no shorter duration than thirty seconds should be necessary.

This sound signal can be remembered as ‘TANGO’ in the Morse code. That is, one prolonged blast followed by two short blasts, ▬.

 

 

(b)       A power-driven vessel underway but stopped and making no way through the water shall sound at intervals of not more than 2 minutes two prolonged blasts in succession with an interval of about 2 seconds between them.

 

It should be noted that, as above, sound signals made by a vessel stopped and making no way through the water may be sounded at shorter intervals than two minutes. This should be the case when visibility is restricted to less than two miles, so that the sound signal is sounded more frequently the shorter the range of visibility.

As above, it should be noted that whilst this sound signal should not be easy to confuse with the signals produced by other vessels, a prolonged interval between each signal that is composed of two prolonged blasts with two seconds duration between them should be left in order to avoid confusion with the signal of a vessel making way, such that there should be an interval of at least ten seconds and preferably as much as thirty seconds between each signal.

This sound signal can be remembered as ‘MIKE’ in the Morse code. That is, two prolonged blasts, ▬ ▬.

 

 

(c)        A vessel not under command, a vessel restricted in her ability to manoeuvre, a vessel constrained by her draught, a sailing vessel, a vessel engaged in fishing and a vessel engaged in towing or pushing another vessel shall, instead of the signals prescribed in paragraphs (a) or (b) of this Rule shall, instead of the signals prescribed in paragraphs (a) or (b) of this Rule, sound at intervals of not more than 2 minutes three short blasts in succession, namely one prolonged blast followed by two short blasts.

 

In other words, every vessel apart from a power-driven vessel, or a vessel aground, or a vessel at anchor, as well as fishing vessels and vessels restricted in their ability to manoeuvre that are at anchor, make this sound signal in restricted visibility.

This sound signal, as with the sound signal for a power-driven vessel making way or a power-driven vessel stopped and making no way though the water, can be sounded at intervals of less than two minutes. Common sense dictates that this should be at a minimum of thirty seconds, and certainly greater than ten, although this sound signal cannot be mistaken for any other.

This sound signal can be remembered as ‘GOLF’ in the Morse code. That is, one prolonged blast followed by two short blasts, ▬ ▪ ▪.

 

(d)       A vessel engaged in fishing, when at anchor, and a vessel restricted in her ability to manoeuvre when carrying out her work at anchor, shall instead of the signals prescribed in paragraph (g) of this Rule sound the signal prescribed in paragraph (c) of this Rule.

 

As mentioned before, these vessels make the ‘GOLF’ (▬ ▪ ) sound signal at least every two minutes instead of the sound signals for vessels at anchor. Remember that vessels engaged in mine clearance operations are restricted in their ability to manoeuvre, although they display (in addition to three all-round green lights and/or three balls) the same lights and shapes as power-driven vessels and vessels at anchor, and make sound signals, when in restricted visibility at anchor, as other vessels restricted in their ability to manoeuvre. To remember this rule, remember that fishing vessels are always fishing vessel even when anchoring, and vessels restricted in their ability to manoeuvre are always vessels restricted in their ability to manoeuvre even when anchoring, so they make the same sound signal; GOLF.

 

(e)       A vessel towed or if more than one vessel is towed the last vessel of the tow, if manned, shall at intervals of not more than 2 minutes sound four blasts in succession, namely one prolonged followed by three short blasts. When practicable, this signal shall be made immediately after the signal made by the towing vessel.

 

Remember that the towed vessel only makes this sound signal if it is manned, and only the last vessel in the tow makes this sound signal. This sound signal shall be made immediately after the signal made by the towing vessel, which may be at intervals more frequent than once every two minutes, but this stipulation only exists so long as it is practicable. Therefore, it is possible that a towing vessel and a vessel being towed will make their appropriate sound signals at different times (or the same time) and possibly at different intervals (for example, the towing vessel might make its sound signal once a minute, whereas the tow makes the sound signals once every two).

Note also that although any vessel or object must be lighted, not all towed vessels and no towed objects need make sound signals; only if they are manned, and only the last vessel in the tow makes the sound signal.

Note that the last vessel in the tow, if more than one vessel is being towed, need not necessarily be manned; but another may be. In this situation, the Rules stipulate that none of the towed vessels shall make a sound signal. In fact, this Rule may be interpreted to read that a vessel being towed must make the appropriate sound signal even if it is not being manned, and that a vessel being towed that is not manned is only exempt from making a sound signal if it is the last vessel being towed where more than one vessel is being towed. This is probably not the intended interpretation; probably, any towed vessel not manned is not expected to produce the sound signal.

The towing vessel may be smaller than the vessel being towed, or vice versa, and therefore their sound signalling appliances may have different nominal ranges. Thus, the sound signal of the towing vessel may be heard without the sound signal of the towing vessel being heard (or vice versa, but that would simply be the ‘GOLF’ signal, which is less surprising.)

Only vessels being towed make one prolonged blast followed by three short blasts. Vessels pushed ahead do not. Remember that vessels being towed alongside are lighted as one vessel and display sternlights; these are vessels being towed, and thus do qualify as being able to make the sound signal (if manned) although it may be difficult to determine which one is the last vessel in tow under certain circumstances, that is, if vessels of equal length are being towed alongside either side of the towing vessel. Vessels being pushed ahead are lit as one vessel, but do not display sternlights; they also do not make sound signals.

This sound signal can be remembered as ‘BRAVO’ in the Morse Code. That is, one prolonged blast followed by three short blasts, ▬ ▪ . Under normal circumstances, this can be expected to be heard immediately after the sound signal made by the towing vessel, which is ‘GOLF’ (▬ ▪ ). Therefore, the combined sound signal of a towing vessel and a vessel being towed is normally considered to be ‘GOLF BRAVO’, or ▬ ▪ ▬ ▪ ; that is, one prolonged blast followed by two short blasts, followed by one prolonged blast, followed by three long blasts.

 

(f)         When a pushing vessel and a vessel being pushed ahead are rigidly connected in a composite unit they shall be regarded as a power-driven vessel and shall give the signals prescribed in paragraphs (a) or (b) of this Rule.

 

Vessels thusly connected are also lighted as one vessel, as per Rule 24 (b), so it is best to complete ignore the fact that one vessel is pushing the other and always remember to treat them as power-driven vessels.

 

(g)       A vessel at anchor shall at intervals of not more than one minute ring the bell rapidly for about 5 seconds. In a vessel of 100m or more in length the bell shall be sounded in the forepart of the vessel and immediately after the ringing of the bell the gong shall be sounded rapidly for about 5 seconds in the after part of the vessel. A vessel at anchor may in addition sound three blasts in succession, namely one short, one prolonged and one short blast, to give warning of her position and of the possibility of collision to an approaching vessel.

 

Remember that the sound signal for a vessel at anchor is made at least once a minute, and may be sounded more often, although common sense suggests at the very minimum there should be an interval of at least ten seconds between making sound signals, and preferably as much as twenty or thirty seconds.

This part of the rule applies to vessels at anchor other than fishing vessels or any type of vessel restricted in its ability to manoeuvre at anchor, which make the sound signal described in part (c), that is, one prolonged followed by two short blasts (the ‘GOLF’ signal.)

Note that vessels of less than one hundred metres in length are not required to make the rapid ringing of the bell in the forepart of the vessel, but vessels of more than one hundred metres in length are obliged to make a rapid ringing of the bell in the forepart, in addition to then making a rapid sounding of the gong in the after part of the vessel. Do NOT think that this limit is fifty metres, because vessels less than fifty metres at anchor need only display one all-round white light where it can best be seen, although vessels longer than fifty metres must show two all-round white lights, one in the fore part and one at or near the stern and at a lower level than the one in the fore part; the gong must be sound in the after part of the vessel if the vessel is over ONE HUNDRED METRES in length. To help remember, recall that a vessel of more than one hundred metres in length, when at anchor, must show all available deck and/or working lights, and in restricted visibility, when at anchor, it must ring the bell for five seconds in the fore part and sound the gong for five seconds in the after part.

A vessel at anchor may also make a sound signal with the ship’s whistle to help indicate its position and the possibility of collision. This sound signal can be remembered as ‘ROMEO’ in the Morse code. That is, one short blast followed by one prolonged blast followed by one short blast, in that order, ▪ ▬ ▪.

 

(h)        A vessel aground shall give the bell signal and if required the gong signal prescribed in paragraph (g) of this Rule and shall, in addition, give three separate and distinct strokes on the bell immediately before and after the rapid ringing of the bell. A vessel aground may in addition sound an appropriate whistle signal.

 

Note that this sound signal is either, ‘ring, ring, ring, RING x 5 seconds, ring, ring, ring,’ or it is, ‘ring, ring, ring, RING x 5 seconds, ring, ring, ring, GONG x 5 seconds.’ It follows the rules described in the previous part, part (g).

A vessel aground may also sound an appropriate whistle signal. What signal this is is not stipulated. Presumably, the signal described in Rule 34 (d), that is, five or more short blasts on the ship’s whistle, which is used to indicate that the other vessel is taking insufficient action to avoid a collision, is the most appropriate to use. Making one short, one prolonged, and one short blast, that is, the warning signal for a vessel at anchor, might seem appropriate, but it may lead to confusion, and so should be avoided.

 

(i)         A vessel of 12m or more but less than 20m in length shall not be obliged to give the bell signals prescribed in paragraphs (g) and (h) of this Rule. However, if she does not, she shall make some other efficient sound signal at intervals of not more than 2 minutes.

 

This part of the rule stipulates that vessels between 12m and 20m in length don’t have to make the bell signals, that is, the signals for vessels at anchor or aground, but do have to make all the other described signals in restricted visibility that are appropriate for a vessel of its type. It does not describe the sound signal, but an equivalent whistle signal would not be appropriate as it would be confused with one prolonged blast, which would indicate that the vessel is a power-driven vessel underway and making way, not at anchor, when in fact it is, if this part of the Rule applies. Therefore, some sound other than the craft’s whistle should be used.

Note also that the sound is made at least every two minutes, instead of at least every minute. It does not need to be a single sound signal of five seconds duration, nor three sounds, followed by one sound of five seconds, followed by three sounds. It just needs to be ‘efficient’, which means that it does the job, i.e. any sound whatsoever apart from a whistle.

Such a vessel can still make these sound signals if she is able and those who have her command are willing.

 

(j)         A vessel of less than 12m in length shall not be obliged to give the above-mentioned signals but, if she does not, shall make some other efficient sound signal at intervals of not more than 2 minutes.

 

This means that a vessel of less than 12m in length doesn’t have to use a whistle or a bell to make the appropriate sound signals, but any noise. As mentioned in the notes for part (i), a whistle should not be used in lieu of a bell, but there’s nothing to stipulate that the same sound shouldn’t be used instead of both the bell and the whistle, and again, such a craft may use the sound signals described in this Rule if able and willing.

 

(k)        A pilot vessel when engaged on pilotage duty may in addition to the signals prescribed in paragraphs (a), (b) or (g) of this Rule sound an identity signal consisting of four short blasts.

 

A pilot vessel isn’t under any obligation to make this sound signal at all.

If four short blasts are heard, it can only mean, ‘PILOT’. In addition to helping a vessel identify the pilot vessel incoming, this sound signal informs a vessel that she does not need to, for example, reduce her speed to the minimum she can be kept on course if she hears another vessel’s fog signal forward of the beam, because the pilot is coming. This allowance is made under Rule 19 part (e), ‘Except where it has been determined that a risk of collision does not exist…’ This, and a few other very specific situations, are what it was talking about.

 

Rule 36

 

Signals to attract attention

 

If necessary to attract the attention of another vessel any vessel may make light or sound signals that cannot be mistaken for any other signal authorised elsewhere in these Rules, or may direct the beam of her searchlight in the direction of the danger, in such a way as not to embarrass any vessel. Any light to attract the attention of another vessel shall be such that it cannot be mistaken for any aid to navigation. For the purpose of this Rule the use of high-intensity intermittent or revolving lights, such as strobe lights, shall be avoided.

 

By ‘embarrass’ this rule means ‘disrupt the safe navigation of another vessel.’ For example, if you make a signal that is too bright, it might remove the night vision of an officer on the bridge of another vessel, which would hinder the ability of him to identify the lights of other vessels and thus navigate safely; this would ‘embarrass him’.

The gist of this rule is that you shouldn’t use lights described elsewhere in the Rules in order to draw attention to something, or, for that matter, use a source of illumination that might be mistaken for lights used in another rule. The implication is that if necessary, you SHOULD make a signal to attract attention to something that might pose a risk to another vessel.

 

Rule 37

 

Distress signals

 

When a vessel is in distress and requires assistance she shall use or exhibit the signals described in annex IV to these Regulations.

 

These will be listed later and will not be repeated here. The fact that they are explicitly mentioned in the main body of the Rules means, however, that it is very important to recall them.

 

PART E – EXEMPTIONS

 

Rule 38

 

Exemptions

 

Any vessel (or class of vessels) provided that she complies with the requirements of the International Regulations for Preventing Collisions at Sea, 1960, the keel of which is laid or which is at a corresponding stage of construction before the entry into force of these Regulations may be exempted from compliance therewith as follows:

 

(a)       The installation of lights with ranges prescribed in Rule 22, until four years after the date of entry into force of these Regulations.

(b)       The installation of lights with colour specifications as prescribed in section 7 of annex I to these Regulations, until four years after the date of entry into force of these Regulations.

(c)        The repositioning of lights as a result of conversion from Imperial to metric units and rounding off measurement figures, permanent to exemption.

(d)       (i)         The repositioning of masthead lights on vessels of less than 150m in length, resulting from the prescriptions of section 3(a) of annex I to these Regulations, permanent exemption.

            (ii)        The repositioning of masthead lights on vessels of 150m or more in length, resulting from the prescriptions of section 3(a) of annex I to these Regulations, until nine years after the date of entry into force of these Regulations.

(e)       The repositioning of masthead lights resulting from the prescriptions of section 2(b) of annex I to these Regulations, until nine years after the date of entry into force of these Regulations.

(f)         The repositioning of sidelights resulting from the prescriptions of section 2(g) and 3(b) of annex I to these Regulations, until nine years after the date of entry into force of these Regulations.

(g)       The requirements for sound signal appliances prescribed in annex III to these Regulations, until nine years after the date of entry into force of these Regulations.

(h)        The repositioning of all-round lights resulting from the prescription of section 9(b) of annex I to these Regulations, permanent exemption.

 

This rule is, effectively, obsolete. The only ships which are likely to exceed thirty years in age are those of historical interest; any vessel that the mariner is likely to encounter will comply with the Rules. Only very old vessels might deviate from the Rules slightly with respect to the position of navigational lights, and knowing that this is what this Rule means is probably all that a mariner will ever need to know about this Rule.

 

Annex I

 

Positioning and technical details of lights and shapes

 

Most of this annex concerns the positioning of lights. This is relevant to the seafarer, but for the most part, the positioning of lights as described in Rule 21 and the descriptions of the locations of the lights in PART C of the Rules should be sufficient. Most of this section will be of more relevance to the owner or shipbuilder.

Attention is drawn to part 6 of this annex, which describes the minimum sizes and placement of shapes, and part 8, which describes the nominal ranges of certain lights. Part 13 will be of value to seafarers working on board high speed craft, or expecting to encounter such craft.

 

1       Definition

 

The term height above the hull means height above the uppermost continuous deck. This height shall be measured from the position vertically beneath the location of the light.

 

2       Vertical positioning and spacing of lights

 

(a)       On a power-driven vessel of 20m or more in length the masthead lights shall be placed as follows:

 

            (i)         the forward masthead light, or if only one masthead light is carried, then that light, at a height above the hull of not less than 6m, and, if the breadth of the vessel exceeds 6m, then at a height above the hull not less than such breadth, so however that the light need not be placed at a greater height above the hull than 12m;

            (ii)        when two masthead lights are carried the after one shall be at least 4.5m vertically higher than the forward one.

 

(b)       The vertical separation of masthead lights of power-driven vessels shall be such that in all normal conditions of trim the after light will be seen over and separate from the forward light at a distance of 1000m from the stem when viewed from sea-level.

 

(c)        The masthead light of a power-driven vessel of 12m but less than 20m in length shall be placed at a height above the gunwale of not less than 2.5m.

 

(d)       A power-driven vessel of less than 12m in length may carry the uppermost light at a height of less than 2.5m above the gunwale. When, however, a masthead light is carried in addition to sidelights and a sternlight or the all-round light prescribed in Rule 23(d)(i) is carried in addition to sidelights, then such masthead light or all0round light shall be carried at least 1m higher than the sidelights.

 

(e)       One of the two or three masthead lights prescribed for a power-driven vessel when engaged in towing or pushing another vessel shall be placed in the same position as either the forward masthead light or the after masthead light; provided that, if carried on the aftermast, the lowest after masthead light shall be at least 4.5m vertically higher than the forward masthead light.

 

(f)         (i)         The masthead light or lights prescribed in Rule 23(a) shall be so placed as to be above and clear of all other lights and obstructions except as described in subparagraph (ii).

 

            (ii)        When it is impracticable to carry the all0round lights prescribed by Rule 27(b)(i) or Rule 28 below the masthead lights, they may be carried above the after masthead light(s) or vertically in between the forward masthead light(s) and after masthead lights(s), provided that in the latter case the requirement of section 3(c) of this annex shall be complied with.

 

(g)       The sidelights of a power-driven vessel shall be placed at a height above the hull not greater than three quarters of that of the forward masthead light. They shall not be so low as to be interfered with by deck lights.

 

(h)        The sidelights, if in a combined lantern and carried on a power-driven vessel of less than 20m in length, shall be placed not les than 1m below the masthead light.

 

(i)         When the Rules prescribed two or three lights to be carried in a vertical line, they shall be spaced as follows:

 

            (i)         on a vessel of 20m in length or more such lights shall be spaced not less than 2m apart, and the lowest of these lights shall, except where a towing light is required, be placed at a height of not less than 4m above the hull;

            (ii)        on a vessel of less than 20m in length such lights shall be spaced not less than 1m apart and the lowest of these lights shall, except where a towing light is required, be placed at a height of not less than 2m above the gunwale;

            (iii)       when three lights are carried they shall be equally spaced.

 

(j)         The lower of the two all0round lights prescribed for a vessel when engaged in fishing shall be at a height above the sidelights not less than twice the distance between the two vertical lights.

 

(k)        The forward anchor light prescribed in Rule 30(a)(i), when two are carried, shall not be less than 4.5m above the after one. On a vessel of 50m or more in length this forward anchor light shall be placed at a height of not less than 6m above the hull.

 

3       Horizontal positioning and spacing of lights

 

(a)       When two masthead lights are prescribed for a power-driven vessel the horizontal distance between them shall not be less than one half of the length of the vessel but need not be more than 100m. The forward light shall be placed not more than one quarter of the length of the vessel form the stem.

 

(b)       On a power-driven vessel of 20m or more in length the sidelights shall not be placed in front of the forward masthead lights. They shall be placed at or near the side of the vessel.

 

(c)        When the lights prescribed in Rule 27(b)(i)            or Rule 28 are placed vertically between the forward masthead light(s) and the after masthead light(s) these all-round lights shall be placed at a horizontal distance of not less than 2m from the fore-and-aft centreline of the vessel in athwartship direction.

 

(d)       When only one masthead light is prescribed for a power-driven vessel, this light shall be exhibited forward of amidships; except that a vessel of less than 20m in length need not exhibit this light forward of amidships but shall exhibit it as far forward as is practicable.

 

4       Details of location of direction-indicating lights for fishing vessels, dredgers, and vessels engaged in underwater operations

 

(a)       The light indicating the direction of the outlying gear from a vessel engaged in fishing as prescribed in Rule 26(c)(iii) shall be placed at a horizontal distance of not less than 2m and not more than 6m away from the two all-round red and white lights. This light shall be placed not higher than the all-round white light prescribed in Rule 26(c)(i) and not lower than the sidelights.

 

(b)       The lights and shapes on a vessel engaged in dredging or underwater operations to indicate the obstructed side and/or the side on which it is safe to pass, as prescribed in Rule 27(d)(i) and (ii), shall be placed at the maximum practical horizontal distance, but in no case less than 2m, from the lights or shapes prescribed in Rule 27(b)(i) and (ii). In no case shall the upper of these lights or shapes be at a greater height than the lower of the three lights or shapes prescribed in Rule 27(b)(i) and (ii).

 

5       Screens for sidelights

 

The sidelights of vessels of 20m or more in length shall be fitted with inboard screens painted matt black, and meeting the requirements of section 9 of this annex. On vessels of less than 20m in length the sidelights, if necessary to meet the requirements of section 9 of this annex, shall be fitted with inboard matt black screens. With a combined lantern, using a single vertical filament and a very narrow division between the green and red sections, external screens need not be fitted.

 

6       Shapes

 

(a)       Shapes shall be black and of the following sizes:

 

            (i)         a ball shall have a diameter of not less than 0.6 m;

            (ii)        a cone shall have a base diameter of not less than 0.6, and a height equal to its diameter;

            (iii)       a cylinder shall have a diameter of at least 0.6m and a heigh of twice its diameter;

            (iv)       a diamond shape shall consist of two cones as defined in (ii) above having a common base.

 

(b)       The vertical distance between shapes shall be at least 1.5m.

 

(c)        In a vessel of less than 20m in length shapes of less dimensions but commensurate with the size of the vessel may be used and the distance apart may be correspondingly reduced.

 

7       Colour specification of lights

 

The chromaticity of all navigation lights shall conform to the following standards, which lie within the boundaries of the area of the diagram specific for each colour by the International Commission on Illumination (CIE).

 

The boundaries of the area for each colour are given by indicating the corner co-ordinates, which are as follows:

 

            (i)         White

 

            x          0.525  0.525  0.452  0.310  0.310  0.443

            y          0.382  0.440  0.440  0.348  0.283  0.382

 

            (ii)        Green

 

            x          0.028  0.009  0.300  0.203

            y          0.385  0.723  0.511  0.356

 

(ii)        Red

 

            x          0.680  0.660  0.735  0.721

            y          0.320  0.320  0.265  0.259

 

 

(ii)        Yellow

 

            x          0.612  0.618  0.575  0.575

            y          0.382  0.382  0.425  0.406

 

8       Intensity of lights

 

(a)       The minimum luminous intensity of lights shall be calculated by using the formula:

                                                I = 3.43 × 106 × T × D2 × K-D

 

where              I           is luminous intensity in candelas under service conditions,

                        T          is threshold factor 2 × 10-7 lux,

                        D         is range of visibility (luminous ranges) of the light in nautical miles,

                        K         is atmospheric transmissivity.

 

                                    For prescribed lights the value of K shall be 0.8, corresponding to a meteorological visibility of approximately 13 nautical miles.

 

(b)       A selection of figures derived from the formula is given in the following table:

 

Range of visibility (luminous range) of light nautical miles

Luminous intensity of light in candelas for K = 0.8

D

I

1

0.9

2

4.3

3

12

4

27

5

52

6

94

 

NOTE:  The maximum luminous intensity of navigation lights should be limited to avoid undue glare. This shall not be achieved by a variable control of the luminous intensity.

 

9       Horizontal sectors

 

(a)       (i)         In the forward direction, sidelights as fitted on the vessel shall show the minimum required intensities. the intensities shall decrease to reach practical cut-off between 1° and 3° outside the prescribed sectors.

            (ii)        For sternlights and masthead lights and at 22.5° abaft the beam for sidelights, the minimum required intensities shall be maintained over the arc of the horizon for up to 5° within the limits of the sectors prescribed in Rule 21. From 5° within the prescribed sectors the intensity may decrease by 50% up to the prescribed limits; it shall decrease steadily to reach practical cut-off at not more than 5° outside the prescribed sectors.

 

(b)       (i)         All-round lights shall be so located as not to be obscured by masts, topmasts or structures within angular sectors of more than 6°, except anchor lights prescribed in Rule 30, which need not be placed at an impracticable height above the hull.

            (ii)        If it is impracticable to comply with paragraph (b)(i) of this section by exhibiting only one all-round light, two all-round lights shall be used suitably position or screened so that they appear, as far as practicable, as one light at a distance of one mile.

 

10     Vertical sectors

 

(a)       The vertical sectors of electric lights fitted, with the exception of lights on sailing vessels underway, shall ensure that:

 

            (i)         at least the required minimum intensity is maintained at all angles from 5° above to 5° below the horizontal;

            (ii)        at least 60% of the required minimum intensity is maintained from 7.5° above to 7.5° below the horizontal.

 

(b)       In the case of sailing vessels underway the vertical sectors of electric lights as fitted shall ensure that:

 

            (i)         at least the required minimum intensity is maintained at all angles from 5° above to 5° below the horizontal;

            (ii)        at least 50% of the required minimum intensity is maintained from 25° above to 25° below the horizontal.

 

(c)        In the case of lights other than electric these specifications shall be met as closely as possible.

 

11     Intensity of non-electric lights

 

Non-electric lights shall so far as practicable comply with the minimum intensities, as specified in the table given in section 8 of this annex.

 

12     Manoeuvring light

 

Notwithstanding the provisions of paragraph 2(f) of this annex, the manoeuvring light described in Rule 34(b) shall be placed in the same for-and-aft vertical plane as the masthead light or lights and, where practicable, at a minimum height of 2m vertically above the forward masthead light, provided that it shall be carried not less than 2m vertically above or below the after masthead light. On a vessel where only one masthead light is carried, the manoeuvring light, if fitted, shall be carried where it can best be seen, not less than 2m vertically apart from the masthead light.

 

13     High-speed craft*

 

(a)       The masthead light of high-speed craft may be placed at a height related to the breadth of the craft lower than that prescribed in paragraph 2(a)(i) of this annex, provided that the base angle of the isosceles triangles formed by the sidelights and masthead light, when seen in end elevation is not less than 27°.

 

(b)       On high-speed craft of 50m or more in length, the vertical separation between the foremast and mainmast light of 4.5m required by paragraph 2(a)(ii) of this annex may be modified provided that such distance shall not be less than the value determined by the following formula:

 

            y = (a + 17Ψ)C + 2

                        1000

 

where: y          is the height of the mainmast light above the foremast light in metres;

                        a          is the height of the foremast light above the water surface in service condition in metres;

                        Ψ         is the trim in service condition in degrees;

                        C         is the horizontal separation of masthead lights in metres.

 

* Refer to the International Code of Safety for High-Speed Craft, 1994 and the International Code of Safety for High-Speed Craft, 2000.

 

14     Approval

 

The construction of lights and shapes and the installation of lights on board the vessel shall be to the satisfaction of the appropriate authority of the State whose flag the vessel is entitled to fly.

 

Annex II

 

Additional signals for fishing vessels fishing in close proximity

 

It is in no way unusual to encounter fishing vessels working as part of a fleet. Not that this rule only applies to such vessels; none of these signals need be used by vessels operating alone. Seafarers will need to be as familiar with these Rules as well as those for fishing vessels. Note also that all of these Rules apply to trawlers, and no other types of vessel.

 

1       General

 

The lights mentioned herein shall, if exhibited in pursuance of Rule 26(d), be placed where they can best be seen. They shall be at least 0.9m apart but at a lower level than lights prescribed in Rule 26(b)(i) and (c)(i). The lights shall be visible all round the horizon at a distance of at least 1 mile but at a lesser distance than the lights prescribed by these Rules for fishing vessels.

 

Rule 22 describes the visibility of lights. For vessels of less than 12m in length, sidelights have a nominal visibility of 1 mile; for vessels more than 12m in length, the minimum nominal range of visibility is 2 miles, and for vessels greater than 50m in length, the minimum nominal range of any light is 3 miles. Therefore, the maximum intensity for the lights described by this annex is 1 mile for vessels of less than 12m in length, 2 miles for vessels greater than 12m in length, and 3 miles for vessels greater than 50m in length. The minimum nominal range of visibility of those lights is 1 mile.

 

2       Signals for trawlers

 

(a)       Vessels of 20m or more in length when engaged in trawling, whether using demersal or pelagic gear, shall exhibit:

 

            (i)         when shooting their nets:

                        two white lights in a vertical line;

            (ii)        when hauling their nets:

                        one white light over one red light in a vertical line;

            (iii)       when the net has come fast upon an obstruction:

                        two red lights in a vertical line.

 

The International Code of Signals flags for the activity described in parts (i), (ii) and (iii) respectively are “Z” or “ZULU”, “G” or “GOLF”, and “P” or “PAPA”.

 

(b)       Each vessel of 20m or more in length engaged in pair trawling shall exhibit:

 

            (i)         by night, a searchlight directed forward and in the direction of the other vessel of the pair;

            (ii)        when shooting or hauling their nets or when the nets have come fast upon an obstruction, the lights prescribed in 2(a) above.

 

(c)        A vessel of less than 20m in length engaged in trawling, whether using demersal or pelagic gear or engaged in pair trawling, may exhibit the lights prescribed in paragraphs (a) or (b) of this section, as appropriate.

 

3       Signals for purse seiners

 

Vessels engaged in fishing with purse seine gear may exhibit two yellow lights in a vertical line. These lights shall flash alternately every second and with equal light and occultation duration. These lights may be exhibited only when the vessel is hampered by its fishing gear.

 

A purse seiner is a type of trawler, although it is not stated so here. The lights, although they are literally flashing, are not to be considered ‘flashing lights’ as defined by Rule 21 part (f).

 

Annex III

 

Technical details of sound signal appliances

 

As the title suggests, this annex is largely technical, and will be of more value to the shipbuilder than to the seafarer, who has no means of accurately measuring sound at sea. Part 1 (c) is of particular value to the seafarer, since it describes the nominal ranges of whistles, which is of particular importance as relates to Rule 35, and PART D of the Rules in general.

 

1       Whistles

 

(a)       Frequencies and range of audibility

 

The fundamental frequency of the signal shall lie within the range 70-700 Hz. The range of audibility of the signal from a whistle shall be determined by those frequencies, which may include the fundamental and/or one or more higher frequencies, which lie within the range 180-700 Hz (± 1%) for a vessel of 20m or more in length, or 180-2100 Hz (± 1%) for a vessel of less than 20m in length and which provide the sound pressure levels specified in paragraph 1(c) below.

 

(b)       Limits of fundamental frequencies

 

To ensure a wide variety of whistle characteristics, the fundamental frequency of a whistle shall be between the following limits:

 

(i)         70-200 Hz, for a vessel 200m or more in length;

(ii)        130-350 Hz, for a vessel 75m but less than 200m in length;

(iii)       250-700 Hz, for a vessel less than 75m in length.

 

(c)        Sound signal intensity and range of audibility

 

A whistle fitted in a vessel shall provide, in the direction of maximum intensity of the whistle and at a distance of 1m from it, a sound pressure level in at least one ⅓-octave band within the range of frequencies 180-700 Hz (± 1%) for a vessel of 20m or more in length, or 180-2100 Hz (± 1%) for a vessel of less than 20m in length, of not less than the appropriate figure given in the table below.

 

Length of vessel in metres

⅓-octave band level at 1m in dB referred to 2×10-5N/m2

Audibility range in nautical miles

200 or more

143

2

75 but less than 200

138

1.5

20 but less than 75

130

1

Less than 20

120*

0.5

 

115†

 

 

111‡

 

 

*           When the measured frequencies lie within the range 180-450 Hz

          When the measured frequencies lie within the range 180-450 Hz

          When the measured frequencies lie within the range 180-450 Hz

 

The range of audibility in the table above is for information and is approximately the range at which a whistle may be heard on its forward axis with 90% probability in conditions of still air on board a vessel having average background noise level at the listening posts (taken to be 68 dB in the octave band centred on 250 Hz and 63 dB in the octave band centred on 500 Hz)

 

In practice the range at which a whistle may be heard is extremely variable and depends critically on weather conditions; the values given can be regarded as typical but under conditions of strong wind or high ambient noise level at the listening post the range may be much reduced.

 

(d)       Directional properties

 

The sound pressure level of a directional whistle shall be not more than 4 DB below the prescribed sound pressure level on the axis at any direction in the horizontal plane within ±45° of the axis. The sound pressure level at any other direction in the horizontal plane shall be not more than 10 dB below the prescribed sound pressure level on the axis, so that the range in any direction will be at least half the range on the forward axis. The sound pressure level shall be measured in that ⅓-octave band which determines the audibility range.

 

(e)       Positioning of whistles

 

When a directional whistle is to be used as the only whistle on a vessel, it shall be installed with its maximum intensity directed straight ahead.

 

A whistle shall be placed as high as practicable on a vessel, in order to reduce interception of the emitted sound by obstructions and also to minimise hearing damage risk to personnel. The sound pressure level of the vessel’s own signal at listening posts shall not exceed 110 dB (A) and so far as practicable should not exceed 100 dB (A).

 

(f)         Fitting of more than one whistle

 

If whistles are fitted at a distance apart of more than 100m, it shall be so arranged that they are not sounded simultaneously.

 

(g)       Combined whistle systems

 

If due to the presence of obstructions the sound field of a single whistle or one of the whistles referred to in paragraph I(f) above is likely to have a zone of greatly reduced signal level, it is recommended that a combined whistle system be fitted so as to overcome this reduction. For the purposes of the Rules a combined whistle system is to be regarded as a single whistle. The whistles of a combined system shall be located at a distance apart of not more than 100m and arranged to be sounded simultaneously. the frequency of any one whistle shall differ from those of the others by at least 10 Hz.

 

2       Bell or gong

 

(a)       Intensity of signal

 

A bell or gong, or other device having similar sound characteristics shall produce a sound pressure level of not less than 110 dB at a distance of 1m from it.

 

(b)       Construction

 

Bells and gongs shall be made of corrosion-resistant material and designed to give a clear tone. The diameter of the mouth of the bell shall be not less than 300mm for vessels of 20m or more in length. Where practicable, a power-driven bell striker is recommended to ensure constant force but manual operation shall be possible. The mass of the striker shall be not less than 3% of the mass of the bell.

 

3       Approval

 

The construction of sound signal appliances, their performance and their installation on board the vessel shall be to the satisfaction of the appropriate authority of the State whose flag the vessel is entitled to fly.

 

Annex IV

 

Distress signals

 

The distress signals used by vessels at sea are of vital importance to a vessel in distress! All seafarers are required to be able to recognise these signals, and since lives may be at stake, these signals are extremely important. They simply need to be memorised.

 

1          The following signals, used or exhibited either together or separately, indicate distress and need of assistance:

 

(a)       a gun or other explosive signal fired at intervals of about a minute;

(b)       a continuous sounding with any fog-signalling apparatus;

(c)        rockets or shells, throwing red stars fired one at a time at short intervals;

(d)       a signal made by radiotelegraphy or by any other signalling method consisting of the group ▪ (SOS) in the Morse Code;

(e)       a signal made by radiotelephony consisting of the spoken word “Mayday”;

(f)         the International Code of Signal of distress indicated by N.C.;

(g)       a signal consisting of a square flag having above or below it a ball or anything resembling a ball;

(h)        flames on the vessel (as from a burning tar barrel, oil barrel, etc.);

(i)         a rocket parachute flare or a hand-flare showing a red light;

(j)         a smoke signal giving off orange-coloured smoke;

(k)        slowly and repeatedly raising and lowering arms outstretched to each side;

(l)         the radiotelegraph alarm signal;

(m)      the radiotelephone alarm signal;

(n)        signals transmitted by emergency position-indicating radio beacons;

(o)       approved signals transmitted by radiocommunication systems, including survival craft radar transponders.

 

2          The use or exhibition of any of the foregoing signals except for the purpose of indicating distress and need of assistance and the use of other signals which may be confused with any of the above signals is prohibited.

 

3          Attention is drawn to the relevant sections of the International Code of Signals, the Merchant Ship Search and Rescue Manual and the following signals:

 

(a)       a piece of orange-coloured canvas with either a black square and a circle or other appropriate symbol (for identification from the air);

 

(b)       a dye marker.