(pronounced pawn-TOON)  A floating bridge which was constructed by anchoring a series of large, flat-bottomed boats across a waterway and then laying wooden planks across them.  The planks (the "chess") were anchored by side rails and then covered with a layer of soil to protect it and to dampen sounds.  Pontoon bridges were extremely i [..]

Temporary floating bridge made by placing small boats called pontoons next to each other. The pontoons are tied together but not to the land, so the bridge can move with the current of the river or st [..]

a temporary bridge over a river supportd by a number of flat bottomed boats or hollow floats Source: National Monuments Record: Maritime Craft Type Thesaurus