Abstract: A personal watercraft with an exhaust system including a first and second mufflers each disposed in opposite sides of the hull. A manifold pipe communicates the engine with the first muffler. A transfer pipe communicates the first muffler with the second muffler. An outlet pipe communicates the second muffler to the atmosphere at an exhaust point located at an opposite side of the hull. The outlet pipe has a raised portion between the second muffler and the exhaust point so that only rotation of the watercraft in a first rotational direction will cause entrant water in the outlet pipe to flow into the second muffler. The transfer pipe has a raised portion between the first and second mufflers so that only rotation of the watercraft in second rotational direction about the longitudinal axis opposite the first rotational direction will cause water that has flowed into the second muffler to flow into the first muffler.

Abstract: A closed coolant circulating system for a watercraft, for traveling along a surface of a body of water, containing a supply of coolant that is caused to flow through the coolant circulating system. The watercraft comprises a hull and an engine. The watercraft also comprises a heat exchanger formed from heat conductive material and having a fluid path defined therein with an inlet port and an outlet port. The heat exchanger has a heat exchanging exterior surface and is mounted to the hull such that the heat exchanging exterior surface constitutes a portion of the exterior surface of the hull that is normally disposed below the surface of the body of water. The heat conductive material of the heat exchanger allows the heat absorbed by the coolant to dissipate from the coolant to the body of water via the heat exchanging exterior surface as the coolant flows through the fluid path.

Abstract: The invention provides an improved nozzle assembly for waterjet-propelled watercraft such as a personal watercraft. In particular, the invention features an improved reverse gate assembly used to travel in a reverse direction. The reverse gate is linked to the steering-controlling waterjet outlet nozzle and pivots laterally with it to provide significantly enhanced steering response and control when the reverse gate is extended for reverse direction travel of the watercraft. The reverse gate actuation linkage assembly enables such linkage of the reverse gate and the steering-control nozzle member even when the nozzle is configured to pivot vertically (in addition to laterally) to “trim” the attitude of the watercraft in the water. Differential or laterally asymmetric design of the reverse gate compensates for vorticity or swirl in the waterjet to help ensure uniform watercraft performance when travelling in a reverse direction and turning either to the right or to the left.