Southern Boating

Soundproofing Your Boat

How to install soundproofing for quieter cruising

For most, boats are a way to escape the rat race of terrestrial life and an opportunity to enjoy time with family and friends on the water. Relaxing can be difficult, however, when you have to scream over engine or generator noise during conversations or while lying awake at night, listening to the melodious hum of an air conditioning unit. Installation of soundproofing can make a huge difference in onboard noise reduction. Here’s how to transform the hullabaloo of your boat into the peace and tranquility of a floating Zen garden.

The best way to combat noise is by containing it at the source—within an engine compartment, for example. Installation of a good-quality foam soundproofing barrier can reduce engine noise by 10-35 decibels (about 65 percent). Soundproofing material is available in a wide variety of forms, from sprays and paints to foil-backed foam panels. Foam panels are a popular choice and one that’s very effective against airborne noise pollution.

Self-adhesive panels are easy to install (just peel and stick), but you have to plan and position them exactly where you want them the first try, as once they’re in place, you typically can’t reposition them without damaging the foam. Non-adhesive backed panels require spray or brush-on contact adhesives. Most allow a bit of last-minute repositioning, making them easier to work with in tight spaces. Regardless of the adhesives used, panels also require the use of mechanical fasteners (such as screws and fender washers) particularly for overhead horizontal installations. (To prevent gripping and tearing of the foam, wax the screws by running them into a candle prior to use.)

Soft sound shields, such as this one from GSi, provide both installation flexibility and significant noise reduction.

Soundproofing panels can be cut to shape with a box cutter or razor knife but a serrated knife blade will provide a cleaner cut of the foam material itself. Thin sheets of soundproofing material can also be cut with a pair of quality scissors. To ensure the best fit (and avoid cutting snafus), make cardboard templates first to check fit and for use as a cutting guide. Be sure to dry-fit everything prior to applying adhesives or peeling self-adhesive panels.

When planning your installation, remember that sound flows like water meaning you’ll want to use special seal or joining tape that’s provided by the manufacturer to prevent “leaks” at panel joints, etc.

Cables and hoses penetrating the material should be sealed using tight-fitting rubber grommets, while any access hatches should close snugly with a good, tight seal. That being said, any soundproofing installation must provide adequate ventilation for the engine. Required vents and air holes can be quieted using air baffles.

It’s not realistic to expect all noise to be eliminated once soundproofing is installed, but when done correctly you should be able to carry on a conversation at normal volume levels and you’ll notice your cruising becomes much more serene. After all, who wants to yell when trying to relax? Namaste!

Installation tips:

• Read all instructions (soundproofing, adhesives, etc) before starting your project.

• Make templates to check fit prior to cutting panels. Be sure to allow for material thickness at corners.

• Ensure your installation provides adequate ventilation and keeps insulation material above bilge water levels. (Avoid exposure to any wet areas.)

• Provide a minimum clearance of six inches between soundproofing and engine or generator exhaust manifolds.

• Use sharp tools when cutting sound proofing in order to produce clean cuts and also to avoid tearing of reflective foil. The foil or silver facing side should face upward when cutting.

• Handle soundproofing material carefully and avoid folding the material back on itself, which can cause creasing.

• Seal all exposed edges with seam tape to prevent water or other contaminates (fumes, oil, etc.) from entering and degrading sound proofing material.

• Don’t rely on adhesives alone. Use fasteners where appropriate (all overhead and vertical surfaces) to ensure backup in the event of adhesive failure.

• Apply adhesive for and install one panel at a time. Install the top panel first, which lets adjacent vertical panels provide support to the outer edges of the top panel.

• Use seam tape to seal exposed joints and corners. Seam tape can also be used to provide chafe protection at wear points.

— By Frank Lanier, Southern Boating Magazine April 2017