Pontoon effect Pontoon effect The pontoon effect refers to the tendency of a vessel whose flotation depends on lateral pontoons to capsize without warning when a lateral force is applied. The effect can be sudden and dramatic because pontoon boats usually cannot rely on the righting effect of a keel (which contains ballast). The vessel is stable and self-righting up to the point that the centre of gravity shifts past the centre of buoyancy of the ship and the vessel rapidly capsizes. The pontoon effect is theoretically possible whenever the vessel's entire weight exceeds the buoyancy of the pontoon(s) on either side.
Trimaran rigging, many modern and ancient trimarans are explicitly designed for this method of righting. Harnesses pulling on the stern toward the bow, or from the bow toward the stern of capsized trimarans have been shown to be able to successfully turn them end-over-end. Several design features reduce the chance of pitch-pole capsize; these include having wing nets with an open weave designed to reduce windage and decks and nets that shed water easily. The best way to avoid capsize is to reduce sail in heavy weather. Competing with a giant trimaran the BMW Oracle Racing team representing the Golden Gate