Patent ID: 7674147

Claim:
A watercraft comprising: a propeller configured to drive the watercraft; a first engine configured to drive the propeller; a first exhaust port extending at least partially through the propeller to expel exhaust generated by the first engine; a generator set (genset) having a second engine, an alternator configured to be driven by the second engine, and a second exhaust port to receive exhaust generated by the second engine; an exhaust processing device connected to the second exhaust port of the genset comprising: an inner passage to receive exhaust gases from the genset and communicate the exhaust gases to an output port; an exhaust processing element mounted within the inner passage to reduce undesirable components in the exhaust; an outer wall of the exhaust processing device surrounding the inner passage; an insulating passage arranged between the exhaust processing element and the outer wall to receive a flow of water therethrough; an insulating chamber separate from the insulating passage and arranged between the exhaust processing element and the outer wall and having a static insulating medium disposed therein; and wherein the insulating passage and the insulating chamber work in concert to maintain a temperature of the outer wall that is substantially reduced from an operating temperature of the exhaust processing element.