Xerxes' Pontoon Bridges are mentioned in a single short phrase than they are told to have been destroyed, whereas the construction of the replacement bridges is reported almost in every little detail, but without a word about the time consumed in this exercise. This may lead to the assumption that the bridges told to have been destroyed by a storm were used by Herodotus only as a pretext for his vivid description in all details of an outburst of rage of the great king Xerxes and even to quote his furious speech in full. Xerxes' Pontoon Bridges Xerxes' Pontoon Bridges were constructed in
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.