ROR - Rule 8 Action to avoid collision

Section I – Conduct of vessels in any condition of visibility

Rule 8 - Action to avoid collision

(a) Any action taken to avoid collision, 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 closequarters situation provided that it is made in good time, is substantial and does not result in another closequarters 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 vessel are approaching one another so as to involve risk of collision.

Questions & Answers

Q1. What 4 actions can you take to avoid a collision?
A1. Action to avoid collision: 
(i) an early and bold alteration of course, as long as you do not put your vessel into another close quarter situation/risk of collision with another vessel
(ii) slow your vessel down
(iii) stop your vessel
(iv) come astern with your vessel

Q2. Why are you always making an alteration of course, why do you not stop your vessel?
A2. To make sure the risk of collision/close quarter situation is taken out, also the other vessel ill see the change of aspect of your vessel (Visually and by radar)

Q3. If you make an alteration of course, what have you to watch out for?
A3. That you don not put yourself into a close quarter situation with another vessel.

Q4. If you make an alteration of course, why is it dangerous to make a series of small alterations?
A4. Because you could go into a close quarters situation/risk of collision

Q5. If you're unsure about what to do in a situation, what's the best thing to do?
A5. Slow your vessel down, best to stop your vessel altogether.

Q6. Discuss how action to avoid collision should be taken.

A6. Action to avoid collision :

In accordance with the Rules, positive, made in ample time, with regard to good seamanship.

Q7. In the case of Q6, what does good seamanship means?

A7. 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.

Q8. What do you understand by "in ample time"?

A8. In most cases, when risk of collision exist it is easy to determine HOW we should maneauver. But WHEN we one to take action it is a bit more complex and depends to a large extend, on existing circumstances:

The size and speed of the vessel involved, the manoeuvering characteristics (turning circle, stopping distance), type of activities vessel engaged (towing, fishing, dredging), sea room, presence of hazard of navigation, state of sea and weather condition to be considered.

Any action to avoid collision should rather be taken earlier rather than too late especially on large vessel.

Q9. Before taking avoiding action, which points with regards to stand-on vessel must known?

A9. Facts about the stand-on vessel:

Her course, speed, bearing, distance, CPA & TCPA.

Q10. How large should an alteration of course be, to be apparent?

A10. 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°

Q11. Which points should you take into account to make an alteration of course alone in case of risk of collision?

A11. Alteration of course alone:

There must be sufficient sea-room

The action must be made in ample time

The alteration of shall be substantial

Another close-quarters situation shall be avoided

Q12. How can you slacken or reduce a vessel speed?

A12. Slackening of speed:

Reduce the number of revolutions of propeller

Stop engines 

Reverse the means of propulsion

Q13. How can you increase the time to access what action to take when there is a risk of collision?

A13. Advantages of reducing speed:

More time to assess the situation


Better chances of manoeuvring

In case of collision, less damage

Q14. In which cases is it imperative to reduce speed?

A14. It is imperative to reduce speed :


In restricted areas where a helm action is impossible

When other vessels or hazard prevent a helm action

When visibility is restricted

In some crossing situations

Q15. Comment what you understand by "not impede the safe passage of another vessel?

A15. 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

Q16. Is a vessel who's safe passage must no be impeded, fully privileged when risk of collision exist?
A16. 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