Just installed new cockpit speakers...

May 27, 2021
57
Beneteau 37 Chesapeake Bay
I just installed two new 6.5" speakers in the cockpit of my Beneteau 37. I had to cut the holes a little larger than the stock speakers. Two questions:

1. The speakers are marine speakers and came with a foam gasket that I stuck the back side of the speakers. Is that sufficient to seal the holes I cut or should add something else?

2. How do I seal the screw holes? I've read various methods from using silicone or 3M 5200, or 4200, to butyl tape, etc. Some of those methods seem to be more for mounting structural members like deck cleats, etc... Seems like overkill for speaker screws.

Thanks!
 
Jan 11, 2014
13,061
Sabre 362 113 Fair Haven, NY
2. How do I seal the screw holes? I've read various methods from using silicone or 3M 5200, or 4200, to butyl tape, etc. Some of those methods seem to be more for mounting structural members like deck cleats, etc... Seems like overkill for speaker screws.
Water is your enemy. It will invade and go to great lengths to enter your boat. In small amounts it is a nuisance and contributes to mold, mildew, and various unpleasant boat smells. Even small leaks can have disproportionate smells. Seal the screw holes even as small as they may be. Butyl tape is an excellent choice.

This is a good choice for butyl tape. There are a couple of rolls sitting in my tool locker.

 
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Jan 18, 2016
782
Catalina 387 Dana Point
Do you think those little foam gaskets will keep water out? I don't.

4000uv stays plenty flexible. 4200, lifecaulk, etc... Do not use 5200. Do not use any type of silicone ever on a boat, you will regret it later.

Use some sort of polysulfide (lifecaulk) or polyurethane sealant.
 
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May 27, 2021
57
Beneteau 37 Chesapeake Bay
Do you think those little foam gaskets will keep water out? I don't.

4000uv stays plenty flexible. 4200, lifecaulk, etc... Do not use 5200. Do not use any type of silicone ever on a boat, you will regret it later.

Use some sort of polysulfide (lifecaulk) or polyurethane sealant.
So take the speakers out and use 4200 or like caulk in place of the foam gasket and then reinstall the speakers?
 
May 27, 2021
57
Beneteau 37 Chesapeake Bay
Water is your enemy. It will invade and go to great lengths to enter your boat. In small amounts it is a nuisance and contributes to mold, mildew, and various unpleasant boat smells. Even small leaks can have disproportionate smells. Seal the screw holes even as small as they may be. Butyl tape is an excellent choice.

This is a good choice for butyl tape. There are a couple of rolls sitting in my tool locker.

Thanks... How would I use butyl tape on the screw holes? Behind the speaker flange?
 
Jan 11, 2014
13,061
Sabre 362 113 Fair Haven, NY
Many boat manufacturers use large quantities of silicone to adhese and caulk frameless hatchlights and portlights. It's called Dow Corning 795 and it still looks like new on my 22 Y.O. boat.
There are different types of silicon caulk. 795 and Silpruf are architectural glazing caulks which have different properties than the typical marine or hardware store silicon caulk. If the caulk smells like vinegar, then this is the caulk not to use. Silpruf and 795 do not smell.

Polysulfides should not be used with plastic parts as it will degrade the plastic. This may also be true with some other caulks.

Butyl tape is safe for most materials.


So take the speakers out and use 4200 or like caulk in place of the foam gasket and then reinstall the speakers?
If the speakers are a reputable brand and the company designed to speakers for outside, exposed use, then the foam is likely adequate to seal the speakers to the cockpit sides. A little butyl tape around each of the screws will work or use a ring of tape around the edge of the speaker.
 
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