Rule 8 - Action to avoid collision a)Any action to avoid collision shall be taken in accordance with the Rules of this Part and shall, if the circumstances

Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisiona)a) Any action to avoid collision shall be taken in accordance with the 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 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 positive, made in ample time and with due regard to the observance of good seamanship.good seamanship.

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

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

d)d) Action taken to avoid collision with another vessel shall be such as to 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 result in passing at a safe distance. The effectiveness of the action shall be carefully checked until the other vessel is finally past and shall be carefully checked until the other vessel is finally past and clear.clear. 11

Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisione)e) If necessary to avoid collision or allow more time to assess the 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 situation, a vessel shall slacken her speed or take all way off by stopping or reversing her means of propulsion.stopping or reversing her means of propulsion.

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

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

(iii)(iii) A vessel the passage of which is not to be impeded remains 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 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.vessels are approaching one another so as to involve risk of collision.

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Rule 8 - Action to avoid collisionRule 8 - Action to avoid collision

© www.nepia.com

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Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionKeywordsKeywords− 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

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When shall an action contribute to the avoidance When shall an action contribute to the avoidance of a collisionof a collision

When it :

− 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

(Rule 8, § (a))

− is positive

55


When is an action considered positiveWhen 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

66

Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionIn Ample Time

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 exception

(Rule 8, § (a))

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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)

88


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)

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In ample time

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

(Rule 8, § (a))

1010

Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionIn 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 1111

The colregs are not applicable at long range, when the The colregs are not applicable at long range, when the distance between the two ships is so big that the risk of distance between the two ships is so big that the risk of collision does not yet exist: collision does not yet exist: Both vessels are then free to take any actionBoth 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

Rule 8 - Action to avoid collision

Keep in mind that : See also Rule 7, §(a)

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Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionGood seamanshipSeamanship 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 marinerHowever, the practice of good seamanship should be the goal of all.

© wilkipedia 1313

Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionObservance of good seamanship

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

(Rule 8, § (a))

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Rule 8 - Action to avoid collisionRule 8 - Action to avoid collision In order to assess risk of collision clearly, In order to assess risk of collision clearly,

the following facts about the stand-on the following facts about the stand-on vessel should be known :vessel should be known : Her courseHer course Her speedHer speed Her bearingHer bearing Her distanceHer distance Her CPAHer CPA Her TCPAHer TCPA Her bow passHer 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). 1515


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 apparent1616


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

1717


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

1818


Alteration of course and/or speed Rule 8, § (b))

Alteration of speed alone

− 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

Advantages

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-by1919

Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionAlteration 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

2020


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.

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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°

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Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionAlteration of course alone Rule 8, § (c))

Close-quarters situationon the radar screen

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 2323


Small course alterations are not readily apparent

Give-way vessel altered course 10° to Sb

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 give-way vessel is really taking sufficient avoiding action

The privileged vessel will also hesitate whether to apply Rule 17 (a) (ii) or (b)

The give-way vessel shows very little visual action to create a clear avoiding action 2424


Large course alterations (if possible), are the best avoiding action



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

It will not have to recourse on Rule 17 (a) (ii) or (b)

2525


Course alterations at night





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 in accordance with the actual circumstances. HIC AT NUNC (Here and Now) 2626


A classic maneuver is where the give-way vessel alters course to pass astern of the privileged vessel

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

12

34

1

2

3

4

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Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionGeneral considerations 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 collisionand 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

EVERY SITUATION IS DIFFERENT, SO, STRICT RULES CANNOT BE GIVEN

2828


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.

2929



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

3030

Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionPassing 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 close-quarters situation

3131


The effectiveness of the action shall be carefully checked until the other vessel is finally past and clear

3232



In this situation, risk of collision is real and effective.

Action is necessary to avoid a collision

3333


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)

3434

Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionSlackening of speed Rule 8 (e)

According to Rule 6, every vessel is required to proceed at a safe speed at all times

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

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

3535


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)

3636


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 engines2)After a few minutes to give slow astern3)Then give half astern4)Finally give full astern

Seek advise with the Chief Engineer and consult the engine’s manual

3737


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 3838


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”

3939


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

4040


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

4141


Advantages of reducing speed

−More time to assess the situation−Better chances of manoeuvring−In case of collision, less damage

4242


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

4343

Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionDo not impede the passage

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

Rule 8 (f) (i)

4444

Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionDo 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 4545


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 draught’’ In fact, “not to impede” should also apply to: vessels not under command,

vessels restricted in their ability to maneuver (dredgers, buoying ships, cable layers, etc), 4646


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.

4747

Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionDo 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

4848

Rule 8 - Action to avoid collisionRule 8 - Action to avoid collisionDo 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)

4949


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

Summary

5050


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

5151


Always:

• Avoid a collision, but also

• The risk of collision

5252

Documents

Rule 8 - Action to avoid collision a)Any action to avoid collision shall be taken in accordance with the Rules of this Part and shall, if the circumstances