The Collision Regulations "apply to all vessels upon the high seas and in all waters connected therewith navigable by seagoing vessels".
The 'Rules of the Road' are contained in The International Regulations for Preventing Collisions at Sea.
A selection of the rules are given below:
Rule 5
Look-out
Every vessel shall at all times maintain a proper look-out by sight as well as by 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.
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. In determining a safe speed the following factors shall be among those taken into account: (a) By all vessels: (i) The state of visibility; (ii) the traffic density including concentrations of fishing vessels or any other vessels; (iii) the manageability of the vessel with special reference to stopping distance and turning ability in the prevailing conditions; (iv) at night the presence of background light such as from shore lights or from back scatter from her own lights; (v) the state of wind, sea and current, and the proximity of navigational hazards; (vi) the draft in relation to the available depth of water. (b) additionally, by vessels with operational radar: (i) the characteristics, efficiency and limitations of the radar equipment; (ii) any constrains imposed by the radar range scale in use; (iii) the effect on radar detection of the sea state, weather and other sources of interference; (iv) the possibility that small vessels, ice and other floating objects may not be detected by radar at an adequate range; (v) the number location and movement of vessels detected by radar;
(vi) the more exact assessment of the visibility that may be possible when radar is used to determine the range of vessels or other objects in the vicinity.
Rule 9
Narrow Channels (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. (b) A vessel of less than 20 meters 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. (c) A vessel engaged in fishing shall not impede the passage of any other vessel navigating within a narrow passage or fairway. (d) A vessel shall not cross a narrow passage or fairway if such crossing impedes the passage of a vessel which can safely navigate only within such 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. (e) (i) In a narrow channel or fairway when overtaking can take place only when 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). (ii) This rule does not relieve the overtaking vessel of her obligation under Rule 13. (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).
(g) Any vessel shall, if the circumstances of the case admit, avoid anchoring in a narrow channel
Rule 12
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: (i) when each of them has the wind on a different side, the vessel which has the wind on the port side shall keep out of the way of the other; (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; (iii) if the 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 the starboard side, she shall keep out of the way of the other.
(b) For the purposes of this Rule the windward side shall be deemed to be the side opposite that on which the mainsail is carried or, in the case of a square rigged vessel, the side opposite to that on which the largest fore-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. (b) A vessel shall be deemed to be overtaking when coming up with a another vessel from a direction more than 22.5 degrees 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 stern light 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.
(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.
Rule 14
Head-on Situation (a) When two power driven vessels are meeting on reciprocal or nearly reciprocal courses 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. (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 in line or nearly in line and/or both sidelights and by day she observes the corresponding aspect of the other vessel.
(c) When a vessel is in any doubt as to whether such a situation exists she shall assume that it does exist and act accordingly.
Rule 15
Crossing Situation
When two power driven vessels are crossing so as to involve risk of collision, the vessel which has 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.
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. (b) Every vessel shall proceed at a safe speed adapted to the prevailing circumstances and condition of restricted visibility. A power driven vessel shall have her engines ready for immediate maneuver. (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. (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 in course, so far as possible the following shall be avoided: (i) An alteration of course to port for a vessel forward of the beam, other than for a vessel being overtaken; (ii) an alteration of course toward a vessel abeam or abaft the beam. (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 be 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.
Rule 8 Action to avoid Collision
EXPLANATION
(Rule 8 is below Explanation)
Take action and make it early
As soon as you identify a risk of collision, you must identify the correct action to avoid collision to ensure the vessels will pass at ‘a safe distance’. You should then take that action to avoid collision as soon as it is appropriate to do so.
· Action to avoid collision should always be:
· Positive – make a big alteration of course and/or speed.
· Made in good time – which means early.
· Seamanlike – do not make the situation worse for any other ship in the vicinity, assess what they may have to do.
· Easily seen by the other ship(s) – avoid a series of small alterations of course and/or speed.
Remember, a substantial alteration made early is better than a very large alteration made late. The closer you are to the other vessel the greater the risk of collision and the more you will have to do to pass at a safe distance. A vessel traveling at a speed of 20 knots will cover one mile every three minutes.
Small alterations of course and speed are dangerous; they do not often solve the problem and they do not give the other vessel a clear indication of what you are doing. Remember to make appropriate sound and light signals.
You should confirm your action to avoid collision by monitoring the change in CPA. Keep taking compass bearings and checking the situation until the risk of collision is over. And remember your engine – if your ability to alter course is constrained then slow down or stop IRPCS Rule 8 (e).
What is a safe distance?
Vessels crossing the busy Dover Straits may for example endeavour for a CPA with other ships of at least 1nm. The Moving Prohibited Zone in Southampton Water bans small craft from an area 1000m (0.6nm) ahead of large ships (over 150m in length) and 100m (330ft) on either side (See LOCAL NOTICE TO MARINERS No 10 of 2016 Navigation in the Approaches to Cowes: Port of Southampton – Precautionary Area 07 January 2016). In narrow channels CPA between larger vessels will be less. The larger the CPA from other vessels, the better. It is safer for all vessels concerned.
Giving way and not impeding.
If the COLREGs require you ‘not to impede’ or ‘give way to’ another vessel, then you must take very early action to make sure risk of collision does not develop.
If you are the ‘not to be impeded’ or stand-on vessel, then you must always be prepared for the give-way vessel not to take the correct action. If a risk of collision develops, you will have to act – remember the caution in Rule 2 on responsibilities and your continuing responsibilities in Rule 17 on action by the stand-on vessel. SUMMARY Always do something positive and timely to avoid a collision.
RULE 8
Action to Avoid Collision
(a) Any action taken 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.
(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.
(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.
(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.
(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.
(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.
(ii) A vessel required 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.
(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 one another so as to involve risk of collision.