Re: insulation for outboard motor cover?
The noise reduction products that a previous poster referred to are more than just foam. They are usually a laminate of closed cell foam and a layer of either lead or heavy vinyl - to provide mass to deaden certain frequencies. It is designed in this way to work better than simple closed cell foam like a camping pad or closed cell rubber.<br /><br />Another factor that is important in sound deadening is to close up all gaps. The difference between a 99% closed space vs. 100% is quite a bit. If you don't think so, check out the difference in the sound that gets through a totally closed door or window, vs. one that is cracked open just a bit.<br /><br />That said, a lot (most?) of the noise from an outboard comes out the lower unit. This is *especially* true in my case - I run a jet. In addition, because of the need to keep the air intake open, you can't completely sound-seal an outboard cowling. Therefore, while the use of the sound deadening foam will no doubt reduce noise as advertised, it might not be as noticable as you would hope. <br /><br />Now, this opinion is based on thinking about it - not actually trying it. I would try it, but this stuff is heavy and with shipping to where I live (it's not available locally), I decided to try something else.<br /><br />By the way, I did speak with the guys who design and sell this stuff and they are great and will try to provide what they think is best for any individual application.<br /><br />I look at the foam inside the cover of my old motor and gotta think that almost anything would be an improvement. What I have is very thin, open cell foam with a lot of gaps. I bought some fairly heavy weight closed cell black rubber foam from a local industrial supply and plan to glue it in some day. If I ever do, I'll report if I hear any difference.
