Action to Avoid Collision

Action to Avoid Collision
If your are going to make an alteration of course make sure its an early and bold alteration as long as you have plenty sea room

Every alteration must be big enough so the other vessel can see it on his radar

A series of small alterations should be avoided

When making an alteration of course, make sure you don't place your vessel into a close quarter situation/risk of collision with another vessel

When taking action to avoid collision you can do one of 4 things

(1) Make an early and bold alteration of course

(2)slow your vessel down

(3)stop your vessel

(4)come astern with your vessel

If you are ever in doubt your best thing to do is stop your vessel until the risk of collision is past (also gives you more thinking time as to what you can do)

After making an alteration of course, take more bearings to make sure the risk of collision/close quarter situation is past

If you're on a collision course
If you're the stand-on vessel you may alter course as long as your not in a close quarters situation, but if in a close quarters situation you shall alter course (Never get into a close quarter situation if you can help it)

Rule of thumb

From 8 to 12 miles - this is your plotting distance to find out if risk of collision/close quarters situation exists

From 4 to 8 miles - this is your/other vessels action area

below 4 miles - close quarters situation (out in the open sea, you should have no vessel within 4 miles)

What you have to do in any situation


(1) Take a series of compass, radar and visual bearing to see if a "Risk of Collision/close quarters situation exists"

(2) Figure out who the giveway/stand-on vessel is

(3) If your the stand-on vessel then use (A) below

(4) If your the giveway vessel then use (B) below

(5) If the giveway vessel is standing on then sound 5 or more short and rapid blasts on the ships whistle or flash your masthead light rapidly 5 or more times, if you get no response then use (C) below

(A) Stand-on with caution, maintaining your course and speed, keep taking bearings to make sure the giveway vessel givesway

(B) As long as there is pleanty sea-room, make an early and bold alteration towards the giveway vessel, give him plenty sea-room, if not a lot of sea-room stop your vessel and let him pass

(C) Make an bold alteration away from this vessel (he could be a pirate vessel)