Pontoon bridge Roman Emperor crossed the Adige in 1157 on a pontoon bridge built in advance by the people of Verona on orders of the German Emperor. The French Royal Army of King Philip II of France constructed a pontoon bridge across the Seine to seize Les Andelys from the English at the Siege of Château Gaillard in 1203. During the Fifth Crusade, the Crusaders built two pontoon bridges across the Nile at the Siege of Damietta (1218-1219), including one supported by 38 boats. On 27 May 1234, Crusader troops crossed the river Ochtum in Germany on a pontoon bridge during the
Pontoon effect each pontoon can support the vessel's entire weight (plus any lateral forces that arise like wind), the center of gravity cannot move transversely beyond the center of buoyancy at the most extreme tipping angle, and the pontoon effect cannot occur. Note, however, that this is not the sole effect to be taken into consideration when assessing the likelihood of capsize. The change in hull windage as the vessel heels is also important. In the case of a trimaran designed for cruising, with solid wing decks (as opposed to racing-type designs with mesh or open wings), those with wide-beam floats able