This standard [10.1] is mandatory for non-private boats to help rescue someone who has fallen into the water.

It's also recommended that privately owned boats carry at least one life-buoy, in a readily accessible position, so that it can be used immediately. [10.1]

After passing a boat coming from the opposite direction, a boater was horrified to turn around and see one of the crew lose his balance and fall overboard. Quickly knocking the engine into neutral, the boater grabbed his life-buoy and threw it directly at the man overboard. Unfortunately the man didn't see the life-buoy coming, and as a result was knocked unconscious when the life ring hit him. Always shout a warning when throwing a life-buoy, and always make sure it is thrown to one side of the person in the water. [10.1]