Abstract: A water jet propulsion apparatus is disclosed having a water conveying conduit with a pump therein and a high efficiency substantially triangular opening flush with the bottom of the craft with a small angle ramp wall inclined upwardly beginning at the apex of the triangle and substantially vertical side walls from the sides of the triangle to the ramp wall. At the opening the sides of the triangle bow outwardly from a true triangle toward the base of the triangle which has a rounded edge. The pump shaft is supported in the conduit in a housing and with the impeller on the end of the shaft and having blades supported on a hub forming passageways within a constant outside diameter but a hub diameter increasing from the inlet side of the impeller to the outlet side. The outlet opening is in the form of two vertical substantially rectangular openings with a steering vane located therebetween and with the outside housing walls forming the openings converging aftwardly toward the steering vane.