Abstract: The marine jet propulsion unit of this invention, in preferred form, has a pair of laterally adjacent blade carriers, each having a vertical outer surface movable in a horizontal orbit and to which blades are fixed that project edgewise outwardly. Each blade has a surface facing in the direction of its orbital movement that is concavely curved along its height. The two blade carriers, at opposite sides of a fore-and-aft extending vertical plane of symmetry, are driven in opposite orbital directions such that each has a driving portion remote from the plane of symmetry that moves rearward in an acceleration channel and has an opposite forwardly moving portion adjacent to the plane wherein its blades are interleaved with those of the other. Water entering a forward intake is guided in two streams, one to the front end of each acceleration channel, and the rear end of each acceleration channel is communicated with a discharging outlet nozzle.

Abstract: A multiple, interleaved friction plate clutch in which the clutch plates have a fluid seal between them to permit fluid pressure to be built up in the space between the plates when they are in the clutch released, separated position, the plate sets are counter-rotating, and the head of oil built up between the plates positively holds both sets of clutch plates normal to the axis of rotation of the clutch and thereby prevents the plates from fluttering, wobbling or having other gyroscopic instabilities.

Abstract: A low noise level, rapidly reversible propulsion system for a submarine or other vessel comprises a non-reversible adjustable speed prime mover, a reversible drive mechanism driven by the prime mover and including a fluid-cooled torque converter and speed reduction apparatus, an energy-dissipating load selectively connectable to the reversible drive mechanism, and a propeller driven by the reversible drive mechanism.

Abstract: An interleaved friction plate clutch in which the interleaved clutch plates can be clampingly engaged to transmit power between the clutch elements. Passage means are provided for cooling and lubricating the surfaces of the clutch plates, which includes a series of circumferentially spaced and axially extending reservoirs located in the clutch hub and radially inwardly of the clutch plates and also including a radially extending slot which extends axially along the length of the reservoir and at one side of the reservoir so as to form a weir therewith in which cooling fluid can accumulate and from which a layer of fluid can then flow over the weir along the entire length of the clutch assembly to thoroughly cool all of the clutch plates.