Abstract: A stabilizing device for a hydrofoil type watercraft embodying a fully submerged hydrofoil. A flywheel is supported for precessive effect and is operatively connected to the steering shaft for effecting movement of the steering shaft and associated hydrofoil for generating a stability force on the hull in response to leaning thereof.

Abstract: A jet propulsion boat having an improved arrangement for rigidly affixing a trim adjusting plate to the underside rear portion of the boat hull and which permits adjustment of the trim angle of the plate. In one embodiment, an angle adjusting means is threadably connected to the trim adjusting plate and passes a threaded fastener that affixes the angle adjusting means and the trim adjusting plate to the hull. In another embodiment, a shim member is interposed between the trim adjusting plate and the hull for effecting trim adjustment of the trim adjusting plate.

Abstract: An induction system for a four-cycle internal combustion engine that improves charging efficiency, power and torque at idle and low speed. A check valve is provided in the intake passage for precluding reverse flow under these running conditions. In addition, a plenum chamber is provided that communicates with the intake passage downstream of the check valve for improving power and torque throughout the entire load and speed range of the engine.

Abstract: An improved suspension system for the drive track of a snowmobile that offers wide amounts of suspension travel and yet is compact enough to be positioned internally of the track. The suspension system permits the use of a tubular shock absorber and a surrounding coil spring for both the front and rear portions of the track. Both front and rear suspension systems embody a link arrangement for moving the ends of the shock absorber and spring toward each other upon upward travel of the track relative to the snowmobile body so as to achieve a wider range of damping for a given degree of suspension travel.