Side-spar cable-stayed bridge of this type (supported by a spar), traveling through a much smaller arc, was one of the original proposals for the eastern span replacement of the San Francisco-Oakland Bay Bridge. Similar bridges, without the spar, could be supported by cables anchored in the canyon walls (where conditions are suitable). This subtype should not be confused with an asymmetrical single tower cable-stayed bridge, which possesses a single tower on one side of the gap to be crossed (see Rama VIII Bridge), nor with the cantilever spar cable-stayed bridge, which has span supporting cables on only one side of the tower along
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.