Pontoon

Pontoon (Fr. ponton; Lat. pons, 'a bridge'), the name given to buoyant vessels used in military operations for supporting a temporary bridge. Marlborough used clumsy wooden pontoons. Napoleon and Wellington had them lighter of tin and copper. They were flat-bottomed, rectangular boats, open at the top. Tin cylinders were then used for some time, but light open boats are now carried by the pontoon troops of the Royal Engineers for large bridges capable of carrying artillery, and Berthon's collapsible boats are sometimes used for small infantry bridges. See BRIDGE, Vol. II. p. 447; and for pontoons in connection with floating-docks, see DOCKS, Vol. IV. p. 32.