Patent ID: 6722934
Filing Date: 2004-04-20
Classification: B63H,F01N

Abstract:
In a marine jet drive in a vessel, the jet drive fixedly mounted in the vessel above the keel at the transom of the vessel and protruding therethrough, and powered by an inboard engine having an exhaust line, the jet drive having an impeller and an impeller housing, a diffusor having a diffusor housing and stator vanes, a nozzle which has a rearward discharge end and is positioned to discharge water from the transom, and a water intake duct at the bottom of the vessel in front of the impeller housing, the improvement wherein:an inner housing (a) is disposed inside the diffusor housing, (b) forms an inner exhaust chamber, (c) has an exhaust discharge tube portion extending rearwardly into the nozzle and terminating in a rearward opening, and (d) is attached to the diffusor housing by the stator vanes; the exhaust line extends from the inboard engine to the diffusor housing; and at least one of the stator vanes is hollow and open at its opposite ends for exhaust flow from the exhaust line to the inner exhaust chamber, so that exhaust exits through the exhaust discharge tube portion at the nozzle into the jet water flow thereby to facilitate removal of exhaust and increase efficiency of operation in a waterjet which is fixedly installed in a vessel and driven by an inboard engine.