Engine Compartment Sound Deadening - Bertram 31

[Ironworker]

Folks,

I need some advice. I'm in the middle of a Bertram 31 renovation project.

These Volvo diesels are loud and I want to add sound deadening material to the inside of the fiberglass engine boxes and close up areas about the boxes to minimize the sound transmission. I'm going to need a good bit of material so cost is a factor. I have a fair amount of clearance between the engine and engine box so, I could use material up to 1" or 1.5"thick. The sound insulation MUST have really good adhesive to stay attached in rough water conditions.

Any ideas or suggestions on sound insulation products? Also I'd appreciate any suggestions regarding the boat renovation.

I'd like to post photos but not sure the best way to do so on this Forum.

Rick Ott

[mike ohlstein]

I used 1.5" Soundown, and along with the glue I used 1 5/8" screws with fender washers to screw into the plywood that's under the top of the engine boxes.

Maybe I'll get some pictures this weekend.

[Ironworker]

Thanks,

I got my boat in the midst of a renovation sitting for 11 years in two different boat yards. There are lots of incomplete parts and some parts missing.

An example, is that my engine covers do not have any wood attached to them. Just the fiberglass.

Thanks for the lead on the 1.5" sound down. Pictures would be great! Another B31 owner suggested Soundown with a lead liner.

[bob lico]

i have soundown with lead and use epoxy on the backside of special clips they give you . the idea is to apply the clips to the fiberglass engine hatches than you install the lead material by just pressing it in place without stabbing yourself with the sharp points then push on the hold downs. has been in my engine compartments for 14 years and still like new.

[Tommy]

I did the same as a Bob and never had the Soundown to sag or separate.

[Carl]

I tried to do the same thing as Bob, but did not get all the old glue off the box insides the prior owner used. So the pins I stabbed myself with multiple times did not hold well in some spots. I highly recommend prepping well.

Also something to consider is the stuff is heavy. If you have an Express where you need to lift and slide box up, to center then up and back onto the deck while standing on the motor IN one motion...the sound down adds ALOT of weight, making removal of box miserable.

The other thing. if you skip a spot, a piece comes off, its amazing how much the noise level changes. A 95% job is almost worthless.

[Ironworker]

I'm hearing impaired so noise is a real issue for me. Plus my crew are lazy louts and I need to holler at them frequently! They pretend not to hear me so I want to go the extra mile to get the boat as quite as possible.

My plan is to spend a good deal of time applying the sound deadening material while trying to maintain some airflow around the engines.

Thanks to all that have made suggestions. They are most appreciated.

[John F.]

I used the vinyl lined instead of lead lined Soundown. It's lighter, but isn't as effective. The Soundown guy was really helpful

[1962 31]

HAS ANYONE TRIED THE DYNA MAT OR FAT MAT ? THE ADHESIVE KIND THAT IS USED IN AUTOMOTIVE WORLD INSTALLATION WOULD BE MUCH EASIER
JUST WONDERING

[Yannis]

Sound insulation is different from sound absorption.

Insulation needs mass. Mass is weight. Weight is lead. Unfortunately.

[Tommy]

Rick,

This would be obvious, but all my work soundproofing the engine boxes was done with the boxes upside-down in the cockpit or workshop. The first thing is to make paper or cardboard templates of the surface area to be covered, then cut your sound deadening material. Determine the spacing of the support pins and epoxy them to the inside of the boxes; the instructions recommend the spacing pattern. After the epoxy sets, you will apply the proper adhesive to both the inside surface of the box and the face of the pre-cut material. With a helper, position and apply the material by placing over the pins and pressing down for 100% contact and the pins protrude through the material. The pins are deadly as others have said, so leather gloves helpful. Then you apply the Keeper-clips to the pins and snip off the excess pin points. I was amazed at the sound-deadening quality of the Sound Down material.

[scenarioL113]

HAS ANYONE TRIED THE DYNA MAT OR FAT MAT ? THE ADHESIVE KIND THAT IS USED IN AUTOMOTIVE WORLD INSTALLATION WOULD BE MUCH EASIER
JUST WONDERING

I have not but would like to hear any reviews myself. I think dynamat and fatmat focus on vibration type noise. They would take more vibration noise out of the hatch covers than muffling the sound of the engines I think.
I am sure you would hear a difference tho.

Would def like to hear other opinions though

[bob lico]

what Tommy said! but i also did bulkhead wall inside engine box area as well as under covering boards,actually the entire engine compartment area is covered in 1 1/2" lead lined SOUNDOWN ,sorry for capital letters but spellcheck refuses to spell words it does not recognize.

[Tommy]

Yes to Bob's added comments; I applied to bulkhead face as well.

[Ironworker]

Rick,

This would be obvious, but all my work soundproofing the engine boxes was done with the boxes upside-down in the cockpit or workshop. The first thing is to make paper or cardboard templates of the surface area to be covered, then cut your sound deadening material. Determine the spacing of the support pins and epoxy them to the inside of the boxes; the instructions recommend the spacing pattern. After the epoxy sets, you will apply the proper adhesive to both the inside surface of the box and the face of the pre-cut material. With a helper, position and apply the material by placing over the pins and pressing down for 100% contact and the pins protrude through the material. The pins are deadly as others have said, so leather gloves helpful. Then you apply the Keeper-clips to the pins and snip off the excess pin points. I was amazed at the sound-deadening quality of the Sound Down material.

Tommy,

Thanks much to you and the others for the information. Its most helpful.

I greatly appreciate everyone's help. Restoration and modernization of an old Bertram in a new experience for me. The more I'm involved with it the more I'm enjoying it.

[Tommy]

You are welcome; it’s what this website is all about. Forgot to add that the company also carries a heavy-duty wide tape to cover all your seams. All the Soundown materials are super high quality.