Patent ID: 7390232

Claim:
An exhaust system for a marine propulsion system having an internal combustion engine having a plurality of exhaust ports and mounted in a marine vessel for propelling the vessel, comprising: a first exhaust conduit member extending from said exhaust ports and conducting exhaust gas therefrom; a second exhaust conduit member extending upwardly from said first exhaust conduit member, said second exhaust conduit member housing a catalyst through which exhaust gas flows; a third exhaust conduit member extending upwardly from said second exhaust conduit member and conducting exhaust gas upwardly and then laterally at a first bend; a fourth exhaust conduit member extending laterally from said third exhaust conduit member and conducting exhaust gas laterally and then downwardly at a second bend; a fifth exhaust conduit member extending from said fourth exhaust conduit member and conducting exhaust gas exteriorly of said vessel, wherein said third and fourth exhaust conduit members are coolant-jacketed, said third exhaust conduit member is coolant-jacketed in a closed-loop cooling system, and said fourth exhaust conduit member is coolant-jacketed in an open cooling system.