Sound insulation 41PC

[Comodave]

One of our projects this winter is to replace the woefully inadequate sound insulation that Formula installed in our 41PC. The factory insulation was .5? foam with some type of vinyl covering that might as well have not been there for all the good it does, or doesn?t do. With the Cummins diesels it is too loud in the cockpit. We bought Soundown 2? 2 pounds per square foot sound insulation. This insulation is very nice. I used the old sound insulation as a template to layout the new insulation. I used a jigsaw with downward cutting teeth to cut out the pattern. It worked well and was very easy to cut. I tried a utility knife first and it was not easy. Today we put the first piece on the bottom of the engine hatch. The Soundown insulation came with PSA on one side and the white mylar on the exposed side. You can get either white mylar or aluminum colored mylar. With the white tape to finish the edges and the white mylar it looks very nice. We predrilled the insulation for the metal pin hangers. We ran the drill backwards to drill through the foam, then forwards to drill through the loaded vinyl layer and then backwards again to get through the bottom layer of foam. Otherwise the foam will wrap up on the drill bit. Then we removed the plastic covering the PSA and inserted the metal pins through the insulation. Then a blob of thickened epoxy on each metal hanger. We put the insulation in place and pushed it firmly up onto the hatch bottom. The PSA is supposed to get stronger over the first 24 hours so we forced the insulation up to the hatch bottom with a couple of ratcheting poles against some 2x4s to hold the insulation tight while the epoxy and PSA setup. This is the first piece and we will leave the support poles in place overnight.

 

[Comodave]

I added the second panel of insulation. We are doing multiple projects on the boat so I am only doing the insulation as I have time. I added 2 blocks where the ladder attaches to the deck so I can mount the ladder lower to allow for the 2? of insulation. The old insulation was only about 1/2? thick so the new insulation wouldn?t fit between the ladder and the deck.

 

[Brians3000gt]

Did you do a decibel check before/after? There's a couple of apps for the phone and I tested mine last year at about 85 dB's which is super annoying. Also may be helpful to know that Walter Air Sep makes a QT air filter that supposedly reduces about 5 dB's of the high pitched turbo noise which would make a huge difference.

 

[Comodave]

No, I didn’t check it before because I didn’t plan on doing the sound insulation this winter. But after the boat was in the barn I decided to do it. The original sound insulation Formula put in was just about worthless since it is .5” foam with a thin vinyl coating on it. The 2” loaded vinyl has to do a lot better.

 

[Brians3000gt]

How big of a roll did you purchase from sound down? And can you link It?

 

[Comodave]

As I remember it comes in 4’6” by 6’ pieces. I bought 2 of them and have quite a bit left over so I will continue insulating the areas surrounding the engine hatch. But that will be done as I have time this summer. I just called their office and ordered it over the phone.