Catamaran Racing Association of Michigan

Definition: The cunningham is a type of downhaul used to change the shape of a sail.  Tightening the cunningham reduces the camber (or fullness) of the sail, reducing drag in heavy air.  It can be a very effective adjustment to manage the power of the mainsail.

The cunningham differs from a typical downhaul in the way that it attaches to the sail. The system usually consists of a line which is secured at one end to the mast or boom below the foot of the mainsail. It is then passed through a cringle in the luff of the sail near the foot, but above the tack, and then led down on the other side to a fitting on the mast or boom or on the crossbar.