Great Isaac - Type: Tugboat, U.S. War Shipping Administration (Navy)Name: All the ships of this class were named for lighthouses in the U.S., except for the Great Isaac, which is in the Bahamas.Built: 1944, Boston MA USASpecs: (185 x 37 ft) 1117 gross tons, 27 crewSunk: Wednesday April 16, 1947 collision with Norwegian freighter Bandeirante - no casualtiesDepth: 90 ft