Scott in Seattle - got a noise solution for ya!
Can't hear the Greatful Dead on your stereo? I've got a break-through idea. And, don't forget, you read it here first!Have you ever noticed how all those big-engined powerboats look a little different than a sailboat? Have you ever wondered why? Well.... they put a flying bridge up there to get away from the engine noise! Soooooo......(just couldn't resist this oportunity!)Well, actually, that may not have been the only reason. I think they may have put the bridge up there so they could see over the bow when underway so it's kinda like killing two birds with one stone.In order to actually add something to this thread, there was an interesting study on sound-proofing on single-engine aircraft several years ago. The project was to sound-proof something like a single engine Cessna or Piper. The firewall between the engine and the cockit was insulated. What was interesting was they found that even the smallest hole or opening in the soundproofing would allow a lot of the noise to get through. A small area that was difficult to get the insulation on, a poorly cut piece of insulation that didn't totally cover everything, etc., all contributed greatly for noise to be transmitted through the firewall. What this points out, like Fred said, is, for a good job, that you got to get ALL insulated. If you're going to do a 90 or 95% job, well, you might as well not even do it.Another point that Fred mentioned that must be considered, is engine breathing. The engine must have a good air intake. If it has to work at geting air, such as sucking it through a well insulated engine room, it won't run properly. Also, if the air is at an elevated temperature it won't run properly either. Providing an air intake duct to the breather as Fred did is an excellent idea for good engine performance.Knocking down that damn engine noise sure does help make life easier. Let's see, a flying bridge on a sailboat..... hmmm...