Abstract: An oar or paddle comprising a shaft having two parallel grooves of circular cross-section extending throughout its length, each groove pivotally supporting a blade. The grooves have a peripheral extent which permits the blades to pivot between a position in which they are parallel and a further position in which they project in opposite directions in a common plane. The blades are located axially of the grooves by retainers which are mounted in the grooves at opposite ends of the portion of the blades disposed within the groove.