| 摘要 |
A water jet propulsion unit for watercraft includes a propeller pump housed in a pump housing (3) which has provided therein an inlet opening (3a) which is connected to a water delivery conduit (6) extending to a water intake opening (7) located beneath the water line of the watercraft, and an outlet opening (3b) through which a jet of propulsion water is generated when the pump is in use. For the purpose of preventing fouling in the water delivery conduit (6), or the formation of ice in the delivery conduit, when the propulsion unit is not in use, there is provided a means (8) for closing the outlet opening (3b) of the pump housing in an essentially airtight manner and means (9, 10) for supplying air under pressure to the delivery conduit (6) in a manner to force from the conduit any water present therein. |
