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. 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. 1
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 searoom 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. 2
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Keywords Positive In ample time Observance of good seamanship Alteration of course and/or speed large enough readily apparent avoid small alterations of course and/or speed Alteration of course alone Close-quarters situation Passing at a safe distance Action shall be carefully checked Slacken speed, take all way off (stop) Do not impede Allow sufficient sea-room Not relieved from obligation Comply with the Rules 4
When shall an action contribute to the avoidance of a collision (Rule 8, (a)) When it : is positive avoids risk of collision avoids a close-quarters situation is taken in accordance with the Rules is made in ample time it is made with the observance of good seamanship 5
When is an action considered positive (Rule 8, (a)) When the action of the give-way vessel does not create any doubt on the stand-on vessel When the give-way vessel does not create a conflicting situation with the stand-on vessel When the give-way vessel communicates her intentions clearly and appropriately by means of sound signals and/or VHF 6
In Ample Time (Rule 8, (a)) So that the stand-on vessel should have no doubt as to the intentions of the give-way vessel Small vessels like yachts must not wait until the last minute to manoeuvre in order to admire the passing ship Larger ships may not think that they always have the right of way. Deep draught vessels may, however, make an 7 exception
General considerations A difference should be made when vessels are in sight of one another (Part B, Section II and when vessels are in restricted visibility (Part B, Section III) The general principle is : one vessel keeps out of the way (the give-way vessel), the other shall keep her course and speed( the stand-on vessel) (Rule 17, (a)) There are two exceptions : Head-on situations, when in sight of one another (Rule 14) and vessels in restricted visibility (Rule 19) 8
According to Rule 16, when vessels are in visual sight of one another, the 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. In that case: The stand-on vessel is required to keep course and speed and, The stand-on vessel will not be justified in taking action herself in accordance with Rule 17 (a) (ii) 9
In ample time (Rule 8, (a)) Enough time to assess the situation clearly Enough time for the OOW not to have to make a decision hastily Enough time so that the OOW can gather enough information Enough time, not to create any confusion or hesitation on the stand-on vessel 10
In ample time (Rule 8, (a)) Young OOW, with little experience, have a tendency to wait too long before they engage in an avoiding action. This creates uncertainty on the other vessel and often causes dreadful decisions on both vessels leading to a collision Never forget that not only a collision should be avoided but also the risk of collision 11
Keep in mind that : See also Rule 7, (a) The colregs are not applicable at long range, when the distance between the two ships is so big that the risk of collision does not yet exist: Both vessels are then free to take any action What is «long range»? This is not quantified in the colregs It varies for each vessel according to her manoeuvring characteristics and dimensions 12
Good seamanship Seamanship is the art of operating a ship or boat. It involves a knowledge of a variety of topics and development of specialized skills including: navigation and international maritime law weather, meteorology and forecasting; watch standing; ship-handling and small boat handling; operation of deck equipment, anchors and cables; rope work and line handling; communications; sailing; engines; execution of evolutions such as towing; cargo handling equipment, dangerous cargoes and cargo storage; dealing with emergencies; survival at sea and search and rescue; fire fighting. The degree of knowledge needed within these areas is dependent upon the nature of the work and the type of vessel employed by a mariner However, the practice of good seamanship should be the goal of all. wilkipedia 13
Observance of good seamanship (Rule 8, (a)) Every action shall be taken with due regard to the observance of the rules of good seamanship, and that means: The action shall be effective Made in ample time Made clearly and positively so as to be sufficiently apparent to the other vessel Due regard shall be paid at all times to the existing dangers of navigation The prescribed signals shall be given on the whistle (see Rule 34) The new course shall be followed without yawning until all risk of collision is over In special circumstances, every action shall be taken with due regard to one s own knowledge and experience Failing to do so will inevitably result in a disaster 14
In order to assess risk of collision clearly, the following facts about the stand-on vessel should be known : Her course Her speed Her bearing Her distance Her CPA Her TCPA Her bow pass Most of these elements have been largely discussed in the previous Rules. They show once more that the use of radar is necessary by day as well as at night (and in restricted visibility). 15
Alteration of course and/or speed (Rule 8, (b)) To avoid a collision, the following main actions may be taken : An alteration of course An alteration of speed An alteration of course and speed Both must be large enough to be readily apparent 16
Alteration of course and/or speed (Rule 8, (b)) By day, at night and in restricted visibility: Indirectly: by means of radar plotting Almost instantaneously: with the ARPA By day and clear visibility: By visual bearings By the silhouette of the vessel (not with air cushion vessels) At night and clear visibility: By visual bearings By the respective positions of the navigation lights 17
Alteration of course and/or speed Rule 8, (b)) Made in ample time Be substantial In other words: In time to be able to properly assess the situation and to have sufficient time to think Large enough to be readily apparent Usually, alterations of speed are observed less rapidly than alterations of course 18
Alteration of course and/or speed Rule 8, (b)) Alteration of speed alone Advantages May be required by Rule 6: Save Speed When there is too little room to alter your course When you need more time to assess the situation Disadvantages Unless drastic, not easily apparent from another vessel (especially on the radar They take more time to materialize even when stopping and applying reverse propulsion In the open sea, the engines are not on stand-by 19
Alteration of course and/or speed Rule 8, (b)) if the circumstances of the case admit, In some situations, large alterations of course and/or speed cannot be made due to: The lack of sea room The presence of hazards to the navigation, Work being carried out (dredging, working on a navigation mark, ) The condition of the vessel (bad stability, small under water clearance, Bank suction, Etc. Whenever possible, avoid a succession of small alterations of course and/or speed 20
Alteration of course alone Rule 8, (c)) This is usually the most effective action to avoid a close-quarters situation, provided: There is sufficient sea-room It is made in good time, It is substantial, It does not result in another close-quarters situation. 21
Alteration of course alone Rule 8, (c)) Amplitude of course alteration Echo trail should turn by at least 20 Alteration of course and speed: at least 30 Alteration of course alone: at least 60 Preferably and recommended: 90 22
Alteration of course alone Close-quarters situation on the radar screen Rule 8, (c)) Ships in the striped area may be considered as being potentially dangerous In open sea: 2 à 3 miles in restricted visibility depending on size and speed abt. 1 mile when in sight of one another In narrow channels: Vessels will inevitably pass closer to one another 23
Alteration of course alone Rule 8, (c)) Small course alterations are not readily apparent Privileged vessel did not alter course Consecutive alterations of 10 or less may seem visible on your vessel (the give-way vessel) but not on the other vessel (the privileged vessel) They will also create a doubt on the privileged vessel whether the giveway vessel is really taking sufficient avoiding action The privileged vessel will also hesitate whether to apply Rule 17 (a) (ii) or (b) Give-way vessel altered course 10 to Sb The give-way vessel shows very little visual action to create a clear 24 avoiding action
Alteration of course alone Rule 8, (c)) Large course alterations (if possible), are the best avoiding action Privileged vessel did not alter course Course alterations of 20 or more (if possible) are clearly visible on both vessels, by day, at night and on the radar This is a clear situation and the privileged vessel now clearly sees that the give-way vessel has taken sufficient avoiding action Give-way vessel altered course 40 to Sb It will not have to recourse on Rule 17 (a) (ii) or (b) 25
Alteration of course alone Rule 8, (c)) Course alterations at night Privileged vessel did not alter course Give-way vessel altered course 40 to Sb Privileged vessel did not alter course Give-way vessel altered course 45 to Sb At night, the give-way vessel should alter course so that on the privileged vessel, first, both sidelights become visible and finally the red sidelight only Remark: Shown situations are only examples. Every situation must be considered 26 in accordance with the actual circumstances. HIC AT NUNC (Here and Now)
2 1 3 4 A classic maneuver is where the giveway vessel alters course to pass astern of the privileged vessel 4 3 2 Both vessels will come on opposite bows. At night a different sidelight should be visible Afterwards, the give-way vessel gradually turns back until the original course is resumed 1 27
General considerations Rule 8 (b) & (c) Small alterations of course and/speed are less visible (especially on the radar) and must be avoided Small alterations of course and/or speed may even increase the risk of collision and end in a close-quarters situation A change of course is usually more effective: For a vessel sighted ahead or fine on the bow For a vessel approaching on Sb at a reasonable distance To avoid an overtaking vessel which fails to keep out of the way Small alterations of course may be confused with the yawning of the vessel A change of speed is usually more effective: If it is a radical alteration For a vessel approaching from abeam or near the beam (thus far from the bow) A change of course and speed are usually necessary: For vessels close to one another 28 EVERY SITUATION IS DIFFERENT, SO, STRICT RULES CANNOT BE GIVEN
Passing at a safe distance Rule 8 (d) The term Safe Distance depends on the circumstances and conditions such as: High seas Channels Traffic density Visibility Navigational hazards Characteristics and maneuverability of own vessel The avoiding action one is taking Etc. 29
Passing at a safe distance Rule 8 (d) In the open sea, with good visibility: One mile or more can generally be considered as a safe distance At night one mile may not be sufficient In restricted visibility when observing by radar: The closest point of approach (CPA) should be between 2 and 3 miles 30
Passing at a safe distance Rule 8 (d) In order to pass astern of a vessel, it is not uncommon to alter course on the stern of the other vessel. The course is being kept on her stern, gradually coming back to the original course THIS MANEUVER IS EXTREMELY DANGEROUS BECAUSE: Vessels will pass too close to each other Vessels will find themselves in a closequarters situation 31
Passing at a safe distance Rule 8 (d) The effectiveness of the action shall be carefully checked until the other vessel is finally past and clear 32
Passing at a safe distance Rule 8 (d) In this situation, risk of collision is real and effective. Action is necessary to avoid a collision 33
Passing at a safe distance Rule 8 (d) Always carefully check the effectivenes of the action Risk of collision remains until the other vessel is past and clear An appreciable change of bearings may not be sufficient to establish that the other vessel will pass clear (especially with large vessels) 34
Slackening of speed Rule 8 (e) According to Rule 6, every vessel is required to proceed at a safe speed at all times According to Rule 19 (b) and (e) a vessel in restricted visibility shall also proceed at a safe speed or take all her way off A reduction of speed may also be required: To avoid a collision To allow more time to asses the situation If necessary, take all way off: By stopping or Reversing the means of propulsion 35
Slackening of speed Rule 8 (e) To reduce the speed of a vessel: Reduce the number of revolutions of propeller Stop engines Reverse the means of propulsion Usually, engines are less powerful when running astern than running ahead With some engines it may be dangerous to apply a crash stop (from full ahead to full astern) 36
Slackening of speed Rule 8 (e) When a crash stop has to be applied on a vessel proceeding at full speed, the engines can become immobilized by reversing too rapidly It is better to reverse the engines to full astern once the vessel s speed has been reduced The best procedure to reverse engines (and to avoid acute cavitation is): 1) To stop the engines 2) After a few minutes to give slow astern 3) Then give half astern 4) Finally give full astern Seek advise with the Chief Engineer and consult the engine s manual 37
Slackening of speed Rule 8 (e) Too often officers hesitate or take too long to carry out an engine action On most vessels moving at full speed ahead, a certain time will elapse before the engines may be reversed. Vessels with variable pitch propellers are an exception On a vessel of abt. 50.000 dwt, and a speed of abt. 15 knots: When the engines are stopped, she will still cover abt. 26 miles When the engines are reversed she will still cover abt. 10 miles A tanker of abt. 200.000 dwt at 16 knots may need: 20 minutes to halve her speed after stopping the engines One hour to stop the vessel with engines stopped Abt. 25 minutes to stop the vessel with engines full astern 38
Slackening of speed Rule 8 (e) DO NOT FORGET: That the frictional resistance of the hull in the water, is directly proportional to the square of the speed This means that the last miles will take much longer than the first miles to bring the vessel to rest When carrying out a crash stop The rudder looses its effect when the engines are stopped Your ship will have swung abt. 90 You can also stop your ship with a Rudder Cycling Stop 39
Slackening of speed Rule 8 (e) Keep the following characteristics of your vessel in mind: The stopping time The stopping distance The turning circle These characteristics must be at the disposal of the OOW and the pilot and any other person engaged in the maneuver of the ship They must be exposed in a visible spot on the bridge 40
Slackening of speed Rule 8 (e) IMO Recommandations on navigational watch The OOW should bear in mind that the engines are at his disposal and he should not hesitate to use them in case of need. However, timely notice of intended variations of engine speed should be given where possible 41
Slackening of speed Rule 8 (e) Advantages of reducing speed More time to assess the situation Better chances of manoeuvring In case of collision, less damage 42
Slackening of speed Rule 8 (e) It is imperative to reduce speed In restricted areas where a helm action is impossible When other vessels or hazards prevent a helm action When visibility is restricted In some crossing situations 43
Do not impede the passage Rule 8 (f) (i) Not to impede the passage means that a vessel shall not hamper, hinder or obstruct the passage of another vessel Some vessels like vessels proceeding in a narrow channel, sailing vessels, fishing vessels, deep draught vessels, etc. often cannot maneuver at liberty or take avoiding action and hence, they should not be impeded in their activities or in their conditional status Not to impede may not be confused with keep out of the way because not to impede is required long before a risk of collision begins to exist Not to impede can also be described as stay away, and don t bother the other vessel. In fact, allow her sufficient sea-room 44
Do not impede the passage Rule 8 (f) (i) Difference between keep out of the way and not to impede Keep out of the way only applies when risk of collision exists and one of the two vessels has to take decisive action to avoid it Not to impede. Risk of collision does not yet exist and the concerned vessel is, in effect, being asked to take early action to avoid such a risk developing For more details regarding the terms: Close-quarters situation, Risk of Collision, Not to Impede and Keep Out of the Way, see Complexity of some Terms after the Rule 19 slides 45
Do not impede the passage Rule 8 (f) (i) Where does the expression not to impede appear Rule 8f: Action to avoid collision Rule 9b: Narrow channels sailing vessels less than 20m Rule 9c: Narrow channels fishing vessels Rule 9d: Narrow channels crossing vessels Rule 10i: Traffic Separation fishing vessels Rule 10j: Traffic Separation sailing vessels less than 20m Rule 18d: Responsibilities between vessels constrained by not draught In fact, to impede should also apply to: vessels not under command, vessels restricted in their ability to maneuver (dredgers, buoying ships, cable layers, etc), 46
Do not impede the passage Rule 8 (f) (i) Rule 8 (f) applies in all conditions of visibility Thus : By day At night In restricted visibility Whether vessels are in sight or not Whether a vessel is only detected on radar Etc. 47
Do not impede the passage Rule 8 (f) (ii) The obligation not to impede the passage or safe passage of another vessel, remains even if a risk of collision already exists In other words: If risk of collision has developed between a not to impede vessel and another vessel, the not to impede vessel will not automatically become a stand-on vessel and the other vessel a give-way vessel The not to impede vessel will not be relieved of her obligation to keep out of the way. Any stand-on action required by any other Rule will be overridden The not to impede vessel will not be relieved of her obligation to also take the necessary action to allow sufficient room for the passage or safe passage of the other vessel 48
Do not impede the passage Rule 8 (f) (iii) When a not to impede vessel and a not to be impeded vessel, have approached one another so as to involve risk of collision, the not to be impeded vessel must obey the Rules of Part B of the Steering and Sailing Rules Both vessels are now expected to take action and to make an alteration This was already underlined in the last part of Rule 8 (f) (ii) which clearly states that the not to impede vessel (e.g. a crossing vessel) shall, when taking action have full regard to the action which may be required by the Rules of this Part (of the not to be impeded vessel) 49
Summary Do not impede the passage Take early action to allow sufficient sea-room Obligation remains if risk of collision exists Take into account the action the other vessel may take If risk of collision exist, the Rules of Part B must be applied 50
This implies that action Shall be effective Made early Be apparent to the other vessel With regard to existing dangers to navigation That the necessary signals shall be given The new course shall be followed without yawing 51
Always: Avoid a collision, but also The risk of collision 52