Pontoon bridge Earl of Shrewsbury crossed the Oise river across a pontoon bridge of portable leather vessels in 1441. Ottoman engineers built a pontoon bridge across the Golden Horn during the Siege of Constantinople (1453), using over a thousand barrels. The bridge was strong enough to support carts. The Ottoman Army constructed a pontoon bridge during the Siege of Rhodes (1480). Venetian pioneers built a floating bridge across the Adige at the Battle of Calliano (1487). The Spanish Army constructed a pontoon bridge at the Battle of Garigliano (1503). The Spanish Army of Flanders under Alexander Farnese, Duke of Parma built an
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.