A ship of the old sailing navies, armed with one, or occasionally two, heavy howitzers or mortars and used for bombarding places ashore. Mostly the mortars were fitted in ketches, either specially built or converted into such from a small three-masted vessel by the removal of its foremast to provide a good deck space forward for the mortars. When employed in bombardment, bomb vessels were moored in position with springs on their cables so that the ships themselves were ‘trained’ for the mortars to fire on the desired bearing. Until 1804, in the British Navy, mortars in bomb vessels were manned and worked by the Royal Artillery; after that date by the newly formed Royal Marine Artillery. The development of naval guns which could be trained and elevated irrespective of the ship's course made all bomb vessels obsolete.
During the latter part of the 18th century and the first half of the 19th century bomb ketches were also used extensively by the British Admiralty to search for the North-West Passage and for the exploration by sea of the Arctic and Antarctic. They were always exceptionally strongly built and had had their decks stiffened with heavy beam bridges to support the shock of the recoil of the heavy mortars and thus were well suited to withstand the pressure of ice when beset by it or frozen in.