Abstract: The assembly includes a propeller shaft, a hollow hub closed at one end and secured at its other end to said shaft, a space being formed within said hub, said hub carrying blades which are rotatably driven by said shaft and hub and are changeable in pitch, a crosshead supported within said space for axially reciprocatable movement and coupled to said blades so as to change the pitch of said blades as said crosshead reciprocates, said crosshead having an end part adjacent said shaft and said end part forming a piston that is slidable on the inner surface of said hub, said piston defining on one side thereof a first chamber formed by said piston, said hub and said output end of said shaft, and defining a second chamber on its opposite side, formed by said piston and said hub, each of said chambers being adapted to be supplied individually with hydraulic fluid. The blades are rotatably connected to the hub, and the connection includes two spaced seals.

Abstract: This disclosure relates to a side thruster for a ship. The thruster includes a propeller mounted in a cylindrical tunnel formed on the ship, and a housing-support is connected between the propeller and the hull of the ship for supporting the propeller in the tunnel. The housing-support extends substantially transversely of the direction of water flow through the tunnel, and it is generally elliptical in cross section. At least one enlargement is formed on the outer surface of the housing-support for reducing the effect of K/a/ rm/a/ n vortexes, and the enlargement preferably spirals around the outer surface of the housing-support.