Water jet propulsion for boat - has improved low loss jet directed onto rudder and variable geometry thrust deflector

摘要

The boat engine drives a set of impellers (3, 4) in a duct, to draw water through intake louvres in the bottom of the hull and expell it via a jet (11) into a square section outlet duct. The jet is designed so that there is no drag from the walls of the larger, square duct, which has a rudder (21) pivotted in the end. For tight turning circles the rudder is turned through 90 deg. to block off the duct, and the thrust leaves the duct out of a ring-shaped port in the bottom of the duct. This port has a set of variable geometry louvres which can be rotated to direct the thrust in any direction.