Abstract: A purse-seine net, lures, or other fish catching devices are used in conjunction with a fishing vessel having a normally closed opening through the side of its hull below waterline. When the purse-seine net is used, a looped opening at the end of the net is placed over and around the opening through the vessel's hull, and the fish are transferred from the net in through the hull, as by suction, into a hold area where they are separated from the sea water; then the sea water is returned to the sea. Trim and stability problems of the vessel are solved by a novel system incorporating one or more compensating tanks, a ballast pump, and novel hull design.