Paul C,
I ordered some of the heavy insulation from Defender. The kit had just enough to insulate the sides and back of the compartment aft of the engine. The back panel is the most important one, in my opinion, because it has small openings into the lazarette area through which sound carries aft and then forward into the quarterberths. I also insulated the wood side panels between the aft engine compartment and the quarterberths.
Another help is to get some of that sticky back padding stuff. Line the contact points of the cabinets, engine cover, and anything else that makes a noise when the engine is running. That vibration creates alot of noise just by rattling the boat.
