Seaborne targets are vessels or floating structures that are shot at for practice by naval or air forces.
Target ships are vessels, typically obsolete or captured warships, used for naval gunnery practice or for weapons testing – perhaps most spectacularly in Operation Crossroads (1946), where 95 ships were sunk in a U.S. nuclear weapons test at Bikini Atoll.
The U.S. Navy employs the Low-Cost Modular Target (LCMT), a modular barge made from pontoons, scaffolding and large colored sails as visual targets, which can be shot at with guns or a variety of missiles.
[1] Navies have used all sort of equipment thrown overboard for gunnery practice, such as empty barrels.
Modern free-floating targets are large, inflatable and bright orange; hence the nickname "killer tomato".