E. Cobham Brewer 1810–1897. Dictionary of Phrase and Fable. 1898.
Bum-boat.
A small wide boat to carry provisions to vessels lying off shore. Also called “dirt-boats,” being used for removing filth from ships lying in the Thames. (Dutch, bumboot, a wide fishing boat. In Canada a punt is called a bun. A bun is a receptacle for keeping fish alive.)
