Water jet propulsion unit for use in water borne craft

摘要

A water jet propulsion unit for water borne craft including two contra rotating impellers, located in an upstream pump housing and a downstream pump housing respectively, and mounted on coaxial shafts. A pressure control priming device in the form of a spring loaded collapsible skirt is located between the impellers. The pressure in the downstream pump housing can be maintained at atmospheric pressure by the controlled admission of air through air inlets.