Soundproofing for Pleasure Craft: Outboard Engine Noise

Soundproofing outboard engine noise
The engine cover of most outboard engines is made from plastic or polyester. These type of engine covers have a weakness, a lack of mass and soundproofing. There are also outboard engines that are placed in a transom, or cover. This often results in reflections of engine noise. The transom can amplify noise which makes the problem even more extensive.

Insulating the outboard engine cover
First of all, you need to measure the amount of space between the engine and cover, allowing you to determine the thickness of the sound insulating material to be applied. Secondly, it's important to know the maximum temperature just under the engine cover, since this plays a big role if any sound absorber can be used at all. We can offer one product, Aluglass, which is 15 mm thick. 

First, start by thoroughly cleaning the cover, which needs to be spotless and degreased. The temperatures under a small engine cover can get quite high. Self-adhesive products have to optimally perform, which is only possible on a really clean engine cover. When applying the Aluglass insulation product, make sure to provide a seamless connection in order to prevent sound leaks as much as possible. You can also make templates from the parts of the cover that you want insulate, to be sure the material will fit when mounting. Make sure that the Aluglass parts cannot touch parts of the engine.

Soundproofing and insulation for the transom
if you cannot soundproof, then insulate the outboard engine cover. If the engine is located in a transom you can insulate the transom, this can be completed by covering as much of the transom with Acousticcell PU. This acoustic foam with a moisture proof protective top layer absorbs engine noise which in turn reduce most of the shrill engine noise.

Suitable products
Information about the mentioned products: