Longboat

1. In the Age of Sail, a double-banked open boat carried by a sailing ship, rowed by eight or ten oarsmen, two per thwart, although designed also to be rigged for sailing; more seaworthy than a cutter or dinghy and with a beam greater than that of a gig. Eventually supplanted by the whaleboat.
2. The largest, and thus the most capable, of boats carried on a ship.
3. Great Lakes slang for a vessel that spends all of her time on any of the five Great Lakes, referring to the slender appearance of such vessels.