Williamson turn
Man-overboard ship-turning manoeuvre — helm hard-over one way, then the opposite, returning the ship to its own wake and the casualty's approximate position.
Regulatory detail & full definition
The Williamson turn is the classic man-overboard recovery manoeuvre. Sequence: full rudder toward the side the casualty went overboard, hold until 60° off original heading, then full rudder opposite way, hold until on reciprocal heading. The ship retraces its wake to approximately the casualty's original position. Preferred at night or in reduced visibility because it reliably returns to the casualty's location without needing continuous visual contact. Alternatives — Anderson turn (fastest), Scharnov turn (fuel-efficient) — trade off between speed + reliability. Every OOW drills all three.
Authoritative source: IMO — SAR ↗
Related
Source: IMO SOLAS + IAMSAR
High confidence
Editorial confidence: how we grade.