[bigeasy1]

I also used Mertons hull and deck putty to bond balsa core to the completely rotted out engine box On my Tsunami.
I used soundown 1-1/4 sound deadening insulation.
As mentioned, it's kind of pricy and it's also pretty heavy. As for its sound reducing quality, I found it to be ok but expected it to perform better.
Don't get me wrong, it does reduce the noise significantly when trolling or motoring at mid to lower engine rpm's but when I run at higer speeds (like hour runs to a fishing spot) I use disposable soft foam earplugs that only cost pennies.They work better than anything.

I bought the Soundown direct from them, but they protect their dealers (understandably) so its actually priced equal to any of the boat or marine supply dealers like Jamestown dist. Hamilton Marine out of Maine stocks it in many thicknesses and sizes and ships everywhere.