Quad scull

A quad scull, or quadruple scull in full, is a rowing boat used in the sport of competitive rowing. It is designed for four persons who propel the boat by sculling with two oars, one in each hand

Racing boats (often called "shells") are long, narrow, and broadly semi-circular in cross-section in order to reduce drag. They usually have a fin towards the rear, to help prevent roll and yaw. Originally made from wood, shells are now almost always made from a composite material (usually carbon-fiber reinforced plastic) for strength and weight advantages. The riggers in sculling apply the forces symmetrically to each side of the boat. Quad sculls is one of the classes recognized by the International Rowing Federation and the Olympics. FISA rules specify minimum weights for each class of boat so that no individual will gain a great advantage from the use of expensive materials or technology.