The Williamson Turn is a maneuver used to reverse the course of a vessel and return along its original track. It is primarily applied during Man Overboard (MOB) situations, especially when the exact position of the casualty is uncertain or when visibility is poor, such as at night or in fog.

Purpose:
• To bring the ship back onto its previous course line, improving the chance of relocating the person who fell overboard.
• Ensures the vessel returns to the point of incident efficiently and safely.
• Helps maintain visual and navigational reference in low-visibility conditions.

Procedure:
1. Apply full rudder toward the side where the person fell overboard.
2. Allow the vessel to deviate 60° from its original course.
3. Shift full rudder to the opposite side.
4. Continue the turn until the vessel is heading about 20° from the reciprocal (opposite) course.
5. Return rudder to midships.
6. Steady the vessel on the reciprocal course and proceed back along the original track to search for and recover the casualty.