1. 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 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.

2. Rule 8 - Action to avoid 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. 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.

3. Rule 8 - Action to avoid collision©

4. Rule 8 - Action to avoid collision
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

5. Rule 8 - Action to avoid collision
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

6. Rule 8 - Action to avoid collision
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

7. Rule 8 - Action to avoid collision
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 exception

8. Rule 8 - Action to avoid collision
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)

9. Rule 8 - Action to avoid collision
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)

10. Rule 8 - Action to avoid collision
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

11. Rule 8 - Action to avoid collision
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

12. Rule 8 - Action to avoid collision
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

13. Rule 8 - Action to avoid collision
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

14. Rule 8 - Action to avoid collision
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

15. Rule 8 - Action to avoid collision
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).

16. Rule 8 - Action to avoid collision
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

17. Rule 8 - Action to avoid collision
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

18. Rule 8 - Action to avoid collision
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

19. Rule 8 - Action to avoid collision
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

20. Rule 8 - Action to avoid collision
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

21. Rule 8 - Action to avoid collision
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.

22. Rule 8 - Action to avoid collision
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°

23. Rule 8 - Action to avoid collision
Alteration of course alone
Rule 8, § (c))
Close-quarters situation
on 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

24. Rule 8 - Action to avoid collision
Alteration of course alone
Rule 8, § (c))
Small course alterations are not readily apparent
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
Privileged vessel did not alter course
Give-way vessel altered course 10° to Sb

25. Rule 8 - Action to avoid collision
Alteration of course alone
Rule 8, § (c))
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)
Privileged vessel did not alter course
Give-way vessel altered course 40° to Sb

26. Rule 8 - Action to avoid collision
Alteration of course alone
Rule 8, § (c))
Course alterations at night
Privileged vessel did not alter course
Privileged vessel did not alter course
Give-way vessel altered course 40° to Sb
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 in accordance with the actual circumstances. HIC AT NUNC (Here and Now)

27. Rule 8 - Action to avoid collision1 2 3 4
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 4 3 2 1

28. Rule 8 - Action to avoid collision
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
EVERY SITUATION IS DIFFERENT, SO, STRICT RULES CANNOT BE GIVEN

29. Rule 8 - Action to avoid collision
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.

30. Rule 8 - Action to avoid collision
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

31. Rule 8 - Action to avoid collision
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 close-quarters situation

32. Rule 8 - Action to avoid collision
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

33. Rule 8 - Action to avoid collision
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

34. Rule 8 - Action to avoid collision
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)

35. Rule 8 - Action to avoid collision
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

36. Rule 8 - Action to avoid collision
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)

37. Rule 8 - Action to avoid collision
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):
To stop the engines
After a few minutes to give slow astern
Then give half astern
Finally give full astern
Seek advise with the Chief Engineer and consult the engine’s manual

38. Rule 8 - Action to avoid collision
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 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 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

39. Rule 8 - Action to avoid collision
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”

40. Rule 8 - Action to avoid collision
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

41. Rule 8 - Action to avoid collision
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

42. Rule 8 - Action to avoid collision
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

43. Rule 8 - Action to avoid collision
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

44. Rule 8 - Action to avoid collision
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

45. Rule 8 - Action to avoid collision
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

46. Rule 8 - Action to avoid collision
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 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),

47. Rule 8 - Action to avoid collision
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.

48. Rule 8 - Action to avoid collision
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

49. Rule 8 - Action to avoid collision
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)

50. Rule 8 - Action to avoid collision
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

51. Rule 8 - Action to avoid collision
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

52. Rule 8 - Action to avoid collision
Always:
Avoid a collision, but also
The risk of collision