A man overboard rescue turn (or person overboard) is a shiphandling manoeuvre usually implemented immediately upon learning of a person having gone overboard into the sea. To bring a vessel closer to the person's location, implementations of the principles described are: the Anderson turn (or single turn), the quick turn (also known as the Q-turn or the figure eight turn), the Williamson turn, and the Scharnow turn.
The man overboard rescue turn is often carried out as part of regular drills on merchant ships as a requirement of the SOLAS Convention. It was named for John Williamson, USNR, who used it in 1943 to recover a man who had fallen overboard. However, according to Uncommon Carriers by John McPhee, the maneuver was originally called the "Butakov pipe" and was used in the Russo-Japanese War as a way of keeping guns at the same distance from an enemy. It was also used by U.S. Navy nuclear submarines to clear their sonar dead zones.
The Williamson turn is the most preferred maneuver by navigating officers onboard ship as it can be used in any condition of visibility and weather. The suitability of the turn depends on the situation:
- Immediate Action Situation: Not as quick as the single turn in an immediate action situation and take the ship further away from the casualty, but it is effective.
- Delayed Action Situation: Mostly it will take the ship to the casualty
- Person Missing Situation: Recommended as it will bring the vessel to its reciprocal course.
A Williamson turn generally consists of: The SMS may include a drill matrix, requiring that the ship's company conduct man overboard drills and Williamson turn drills at regular intervals such as every three months.