Standing or riding on the gunwales or bow of a boat causes most crew-overboard situations. If you must move around in a boat which is underway, stay centered and low, move along the centerline, hold on to both sides and have at least three points of contact with the boat at all times.
Boats react differently than cars; they are steered from the stern and rotate around a pivot point. This pivot point is approximately one-third of the way back from the bow when moving forward. If you find yourself in a crew overboard situation, you should turn in the direction of the person overboard. In the illustration, a person fell off the port side. The skipper should turn the boat to port. This will move the stern (and the propeller) to starboard and away from the person in the water.
Do not go into the water to assist the person unless absolutely necessary. If the victim is unable to board or needs further assistance and someone must go into the water, make sure that person is wearing a PFD and is attached to the boat with a line.