User:Martin of Sheffield/sandbox5

Summary of regulations
The full text of the regulations is available in Wikisource and in numerous on-line alternatives. Each major part and section here is linked to the appropriate text. To avoid meaningless repetitions of the same reference the text is referenced here and at the end of this section only.

Part A – General
The first part defines how the rules are to be applied.

Rule 1 : Application
The rules apply to the "high seas" and all navigable waters connected to them. However Governments are able set rules for men-of-war and for waters within their jurisdiction. Governments may also exempt vessels of "special construction" from parts of the rules.

Rule 2 : Responsibility
All those owning or working on vessels are responsible for keeping the rules and applying them according to the circumstances of the case. The rule accepts that departure from the rules may be necessary to "avoid immediate danger".

Rule 3 : General definitions
The rule defines some terms. Less obvious terms are that a "sailing vessel" is only a sailing vessel if she is not also using power; a fishing boat is only such when using large nets (not rod-and-line); a "vessel not under command" is one unable to manoeuvre; and "underway" means not anchored or made fast, even if not actually moving. There is a list of examples of vessels which are "restricted in her ability to manoeuvre" including working with buoys, pipelines, dredging and replenishing at sea.

Part B – Steering and sailing rules
This part covers the heart of the rules: who gives way to whom and how in a variety of circumstances.

Section I - Conduct of vessels in any condition of visibility
The first section covers the basics of the rules. Later sections deal with good visibility when vessels can see each other and then with poor visibility when they can't.

Rule 4 : Application
The rule simply repeats that the section applies in all conditions of visibility.

Rule 5 : Look-out
The rule mandates that all vessels must keep a look out by all available means, this includes both visual and electronic.

Rule 6 : Safe speed
A safe speed is one where vessels can take action or stop to avoid a collision. Pointers are given including: visibility, other vessels, wind, currents, navigation hazards and draught. Vessels are warned about the limitations of radar in detecting small vessels and debris in various sea conditions.

Rule 7 : Risk of collision
Guidelines on assessing if a risk of collision exists.

Rule 8 : Action to avoid collision
The rule requires a vessel taking action to avoid a collision to do so in plenty of time and in an obvious manner. The action may be a change of course or of speed and must be apparent to the other vessel. In any case, all vessels remain obliged to comply with the rules to avoid a collision.

Rule 9 : Narrow channels
The rule does not define what is a narrow channel but within a narrow channel ships must try to keep to the starboard (right hand side) of the channel. Small boats and sailing vessels must keep out of the way of large vessels which are constrained by the narrowness of the channel. Fishing boats must keep out of the way of all craft on passage, as must vessels crossing the channel. Overtaking is permitted, but sound signals may be required (see rule 34) as they are when approaching blind bends. Vessels should not anchor in narrow channels.

Rule 10 : Traffic separation schemes
Rule 10 is quite complicated and relates to one-way systems set up in areas of high traffic. Vessels must still abide by all other rules.

Larger vessels on a through passage enter and leave the traffic separation scheme (TSS) at its ends only. Smaller vessels generally keep inshore of the TSS lanes, as may large vessels when travelling to and from destinations alongside the TSS (sections (d)(i) and (ii)). Any vessel crossing the TSS must do so at right angles. If joining or leaving part way along a vessel must do so at "as small an angle to the general direction of traffic flow as practicable".

Fishing vessels, small craft and sailing vessels must not impede traffic using the TSS. A vessel restricted in her ability to manoeuvre is generally exempt from this rule.

Rule 11 : Application
Merely states that this section relates to vessels in sight of each other.

Rule 12 : Sailing Vessels
When two sailing vessels are approaching each other it is the wind direction which decides who has to keep out of the way. If the wind is on a different side of each vessel then the one with the wind to port (ie coming from the left) keeps clear of the other. If however the wind is on the same side of both vessels, then the vessel that is upwind keeps clear. If a vessel has the wind on the port and sees another vessel upwind of her, but cannot determine which side the wind is on the other vessel, then she must keep out of the way. The rule gives guidance that the wind is assumed to come from the side opposite to the way the mainsail is carried.

Rule 13 : Overtaking
The rule is simple, an overtaking vessel of any type must keep clear of the other vessel until she is "finally past and clear". The rule defines in detail what is meant by overtaking and in the case of doubt requires vessels assume that they are.

Rule 14 : Head-on situation
This is the standard "keep right" rule for power driven vessels. Turn to starboard (right) and leave the other vessel on your port (left).

Rule 15 : Crossing situation
When two power driven vessels are crossing, the one who can see the other to the starboard (right) is called the "give-way" vessel and must keep out of the way of the other vessel. Normally this is by turning to starboard and passing behind. The other vessel is called the "stand-on" vessel and should maintain course and speed.

Rule 16 : Action by give-way vessel
The give-way vessel has to keep out of the way of the other vessel and should take "early and substantial" action to make it clear she is keeping out of the way.

Rule 17 : Action by stand-on vessel
The rule instructs the stand-on vessel to maintain her course and speed unless the give-way vessel fails to take appropriate action. In that case the stand-on vessel must take appropriate action to avoid a collision. If a stand-on vessel does take such action, she should try to avoid turning to port since to do so increases the chance of a collision.

Rule 18 : Responsibilities between vessels
Except for narrow channels (rule 9), traffic separation schemes (rule 10) and overtaking (rule 13) the rule establishes a precedence: A higher numbered vessel must keep out of the way of a lower numbered vessel.
 * 1) a vessel not under command
 * 2) a vessel restricted in her ability to manoeuvre
 * 3) a vessel engaged in fishing
 * 4) a sailing vessel
 * 5) a power driven vessel

The rule then establishes a few special cases. Any vessel other than case 1 and 2 must keep out of the way of a vessel "constrained by her draught" which is showing the appropriate signal according to rule 28. Essentially, big ships need to keep to the deep water channel and cannot avoid smaller vessels, so small vessels have to keep out of the way, regardless of the precedence. The other special cases are seaplanes (including flying boats) and WIG craft (those flying just above the surface). These two cases must keep out of the way of all other craft.

Rule 19 : Conduct of vessels in restricted visibility
The rule requires vessels to proceed with due caution when visibility is reduced. Vessels need to slow down and be prepared to manoeuvre. If a vessel hears a fog signal forward of her she must slow right down and if necessary stop. There are also rules for when a vessel only detects another by radar alone, essentially it becomes her responsibility, the other vessel may not have radar.

Part C – Lights and shapes
Vessels exhibit distinctive lights to indicate what sort of vessel they are and in which direction they are going. During daylight they display shaped objects to show what they are doing.

Rule 20 : Application
The rule requires lights to be used from dusk to dawn and in reduced visibility, and may be used during daylight, whatever the weather. Other lights must not be exhibited if they could cause confusion. Shapes must be used during daylight.

Rule 21 : Definitions
The types of light and the arcs of visibility are defined.

Rule 22 : Visibility of lights
Lights must be visible for certain minimum ranges depending upon the light type and the vessel size.

Rule 23 : Power-driven vessels underway
Power driven vessels exhibit port and starboard lights, a forward facing mast head light and a sternlight. Large vessels exhibit a second masthead light. Very small vessels may exhibit less lights.

Rule 24 : Towing and pushing
Towing vessels exhibit two or three masthead lights and a diamond shape. The tow is also lit. Rigid push-tows are list as for a single vessel.

Rule 25 : Sailing vessels underway and vessels under oars
Sailing vessels exhibit port, starboard and stern lights. A sailing vessel may also exhibit a red light over a green light. Small sailing vessels exhibit proportionately less lights and a vessel under oars does the same or else a single white light. By day a sailing vessel using her engine exhibits a cone pointing downwards.

Rule 32 : Definitions
The rules defines a whistle, a short blast (about 1 second) and a prolonged blast (4 to 6 seconds).

Rule 33 : Equipment for sound signals

 * Vessels under 12 m must have a means of making a sound.
 * Vessels 12 m to 20 m must have an approved whistle.
 * Vessels 20 m to 100 m must have an approved whistle and a bell.
 * Vessels over 100 m must have a whistle, bell and gong.

Rule 34 : Manoeuvring and warning signals
The following sound signals are used when vessels are in sight of each other:
 * Turning to starboard (right), one short blast.
 * Turning to port (left), two short blasts.
 * Engines going astern, three short blasts.
 * Overtaking to starboard, two long blasts and one short blast.
 * Overtaking to port, two long blasts and two short blasts.
 * Agreeing to being overtaken, long, short, long, short.
 * Other vessel's intentions not understood (aka "Wake up") at least five short and rapid blasts.
 * Approaching a blind bend, a single long blast. If a long blast is heard when approaching a bend also sound a long blast.

Lights may be used in a similar way to supplement these signals.

Rule 35 : Sound signals in restricted visibility
Vessels use sound signals where the visibility is restricted by both day or night. Vessels near an area of restricted visibility must also make the signals so that they will be heard within the area.
 * Power driven vessels sound one long blast at least every 2 minutes.
 * If the vessel is stopped then she makes two long blasts.
 * Where the vessel cannot easily manoeuvre then she makes one long blast followed by two short blasts. This includes:
 * vessels not under command.
 * restricted in their ability to manoeuvre (even if anchored when they are working).
 * constrained by their draught.
 * fishing vessels (even if anchored when they are working).
 * sailing vessels.
 * tows.
 * Anchored: ring a bell for five seconds and if over 100 m sound a gong. An anchored vessel may also sound short, long, short as a further warning.

Rule 36 : Signals to attract attention
Vessels cannot use sound sound or light signals that: to attract attention. Any other sound or light signal can be used though strobes and revolving lights should be avoided.
 * can be mistaken for one of the signals in these rules
 * could be mistaken for a navigation signal (buoys, lighthouses etc)

Rule 37 : Distress signals
The rule refers the reader to the annexe.

Rule 38 : Exemptions
Vessels constructed or under construction prior to the regulations coming into force are granted certain exemptions. The current rules came into force in 1972.

Part F – Verification of Compliance with the provisions of the convention
These three rules define the auditing procedure that the IMO carries out to check that countries are following the code. They do not appear in the 1972 text, but are included in the amended 2016 text.
 * Rule 39 : Definitions
 * Rule 40 : Application
 * Rule 41 : Verification of compliance

ANNEX I : Positioning and technical details of lights and shapes
The annexe gives technical details on the type and positioning of the various lights and shapes.

===ANNEX II : Additional signals for fishing vessels fishing in close proximity===

Three sections describe:
 * The lights used by trawlers to indicate shooting nets, hauling nets and if the nets are stuck.
 * Lights used by pair trawlers.
 * Lights used by purse seiners.

ANNEX III : Technical details of sound signal appliances
The annexe gives technical details ( frequency, power etc) of whistles, bells and gongs.

ANNEX IV : Distress signals
The final annexe lists distress signals and regulates their use. For speed of reference this annexe is quoted in its entirety:

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 sent by radiotelephony consisting of the spoken word "Mayday";
 * (f) the International Code Signal of distress indicated by N.C.;
 * (g) a signal consisting of a square flag having above or below it a ball 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) a distress alert by means of digital selective calling (DSC) transmitted on
 * (i) VHF channel 70, or
 * (ii) MF/HF on the frequencies 2187.5 kHz, 8414.5 kHz, 4207.5 kHz, 6312 kHz, 12577 kHz or 16804.5 kHz;
 * (m) a ship-to-shore distress alert transmitted by the ship’s Inmarsat or other mobile satellite service provider ship earth station;
 * (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, Annex III and the following signals:
 * (a) a piece of orange-coloured canvas with either a black square and circle or other appropriate symbol (for identification from the air);
 * (b) a dye marker.