Propulsion system for boat has gas expansion engine fed with nitrogen gas under pressure fed from high-pressure liquid nitrogen tank via evaporative heat exchanger in wall of duct surrounding propeller

摘要

The boat runs on liquid nitrogen kept in an insulated high-pressure tank (1) inside the hull. The filler cap (2) is situated on top of the tank inside the hull. The boat is steered by a tiller (7) with a direct connection (7) to a pod (15) with an evaporator (3) in its walls, heated by the ambient water (10). There may be a pump to raise the liquid nitrogen to high pressure before evaporation. The pod has a housing (4) containing an expansion engine (12) with a shaft (5) driving a propeller (6). Low-pressure waste nitrogen is discharged to the environment through the hollow boss of the propeller (11).