Raft

A raft is any flat structure for support or transportation over water.[1] It is usually of basic design, characterized by the absence of a hull. Rafts are usually kept afloat by using any combination of buoyant materials such as wood, sealed barrels, or inflated air chambers (such as pontoons), and are typically not propelled by an engine.

Traditional raft, from the 1884 edition of Adventures of Huckleberry Finn