Oscar Flag

Oscar, letter O of the International Code of Signals, is the man-overboard flag, split diagonally with red at the upper hoist and yellow at the lower fly. A ship hoists it singly the moment a person goes over the side, alerting nearby vessels to a rescue in progress and to keep clear of the search area. Bridge teams pair the flag with maneuvering for recovery and, where fitted, an MOB marker or the GMDSS alert.