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Comodave 12-05-2021 10:05 PM

Engine room sound insulation
 
6 Attachment(s)
Our Formula 41PC with 450 Cummins was in need of some better sound insulation than the inadequate sound insulation that was installed by Formula. They put in 1/2Ē foam with a vinyl cover. It looked nice but didnít do much for diesel noise. We are putting in 2Ē 2 pound per square foot insulation. It is comprised of 1Ē foam with PSA bonded to a mineral loaded vinyl layer with another 1Ē of foam bonded to that and topped by a white mylar. We used the old foam as a template to layout the new insulation. Took a jigsaw with a laminate cutting blade (downward cutting teeth) and easily cut out the new insulation. We then drilled holes in the new insulation. Reverse the drill to drill the foam, then forward to drill the loaded vinyl layer and then reverse to drill the bottom layer of foam. We spaced the brackets to hold up the insulation about 9Ē apart. After drilling the holes for the pin brackets we inserted the pins through the insulation from the PSA side. Then put a spoonful of thickened epoxy on each pin bracket. Then the fun part, carefully position the piece of insulation in place. You only get one chance as the PSA will quickly grab onto the substrate. We then used a variety of things to prop the insulation in place overnight. Soundown said the PSA will gain in strength in the first 24 hours so we wanted it held firmly in place for that time. Also the epoxy will take 4 to 6 hours to setup. We had a couple of racheting poles used in pickup beds to hold stuff from sliding around. They turned out to be the perfect thing to hold the insulation in place. We used plywood and 2x4s against the insulation and the rachet poles to put pressure up on the wood. So far it has worked very well. After the PSA and epoxy have setup we removed the supports and cut the pins to lenght. Then put on the one way washers and caps onto the pins.

Lepke 12-05-2021 10:23 PM

Most foam I know of puts out toxic fumes in a fire. It's usually placed outside of enginerooms so there's a barrier between it and any engineroom fire.

rslifkin 12-05-2021 10:25 PM

Quote:

Originally Posted by Lepke (Post 1058179)
Most foam I know of puts out toxic fumes in a fire. It's usually placed outside of enginerooms so there's a barrier between it and any engineroom fire.

It's probably no worse than the fiberglass hatch above it though

Comodave 12-05-2021 11:00 PM

It is designed for engine room sound attenuation and is fire retardant.

fgarriso 12-06-2021 04:54 AM

SoundDown Inc makes a lead foam for sound abatement. It comes in 1"- 4" and they also have sound absorbent underlayment for the cabin soles.

Mako 12-06-2021 05:45 AM

Please share your sound measurements before/after. I recently insulated the cowling of my 2-stroke outboard with 2 lb MLV and realized an 18 db noise reduction.

Keysdisease 12-06-2021 06:36 AM

Nice work :socool:

Mako 12-06-2021 07:46 AM

Thanks but itís still too noise for me on long runs. I find the best way to silence the motor is to turn it off [emoji4]

Cigatoo 12-06-2021 08:01 AM

Quote:

Originally Posted by Keysdisease (Post 1058210)
Nice work :socool:

Agreed. Handy guy to have around :thumb:

thedeltaskipper 12-06-2021 09:54 PM

If you don't mind me asking how much was this 2"/2lb product from Soundown? Did you buy directly from them? Thanks

Comodave 12-06-2021 10:10 PM

Quote:

Originally Posted by fgarriso (Post 1058201)
SoundDown Inc makes a lead foam for sound abatement. It comes in 1"- 4" and they also have sound absorbent underlayment for the cabin soles.

They donít use lead but rather a mineral loaded vinyl in the middle since lead is a hazardous material.

Comodave 12-06-2021 10:11 PM

Quote:

Originally Posted by thedeltaskipper (Post 1058497)
If you don't mind me asking how much was this 2"/2lb product from Soundown? Did you buy directly from them? Thanks

I bought 2 sheets 4.5íx6í and a roll of the mylar edge tape to finish the cut edges. Total was 547.50 plus shipping. I ordered it directly from Soundown.

Comodave 12-06-2021 10:12 PM

Quote:

Originally Posted by Mako (Post 1058208)
Please share your sound measurements before/after. I recently insulated the cowling of my 2-stroke outboard with 2 lb MLV and realized an 18 db noise reduction.

Unfortunately I didn’t measure the before sound levels. Dumb…. When we hauled we didn’t plan on doing the sound insulation because of all the other work we planned, but after the boat was in the barn we decided to go ahead with it this year.

Comodave 12-06-2021 11:08 PM

Honestly I didn’t even look for other sources since we had insulated 4 previous boats with Soundown and had great success with it and was very satisfied with their customer support.

I was posting this reply while the one previous to this was being deleted so this one may not make a lot of sense.

lwarden 12-07-2021 01:00 AM

Quote:

Originally Posted by Comodave (Post 1058508)
Honestly I didnít even look for other sources since we had insulated 4 previous boats with Soundown and had great success with it and was very satisfied with their customer support.

I was posting this reply while the one previous to this was being deleted so this one may not make a lot of sense.

That was my post Dave which I deleted. I posted from soundproofcow.com where I bought it before but realized it wasn't flame retardant foam so although cheaper probably not recommended, at least for engine rooms.

Comodave 12-07-2021 01:21 AM

Quote:

Originally Posted by lwarden (Post 1058524)
That was my post Dave which I deleted. I posted from soundproofcow.com where I bought it before but realized it wasn't flame retardant foam so although cheaper probably not recommended, at least for engine rooms.

No problem we were both working at the same time.

Keysdisease 12-07-2021 07:12 AM

1 Attachment(s)
What stops noise is Mass. Foams and Fiberglass and other "soft" insulations "absorb" noise, but are not noise "barriers."

Lead has significant mass, and is an excellent noise barrier. Mass Loaded Vinyl (MLV,) which Comodave used in the Soundown product, when used in the same weight, presents the same "mass" as lead. Noise doesn't care what the mass is, 2lb sq ft of Lead or 2lb sq ft of MLV reduce noise the same. Lead is more expensive, and as noted, is toxic, so there is no good reason to use lead instead of MLV on these type boats.

When a mass layer is incorporated into a composite with a decoupler layer of foam against the structure (hatch/bulkhead) and an absorption layer exposed to the noise source, the mass layer's performance as a noise barrier is significantly increased.

Lead is still used is some specific applications like Coast Guard inspected vessels and large class yachts, but these are the exceptions, not the rule.

:socool:



Originally Posted by fgarriso
SoundDown Inc makes a lead foam for sound abatement. It comes in 1"- 4" and they also have sound absorbent underlayment for the cabin soles.


Quote:

Originally Posted by Comodave (Post 1058498)
They donít use lead but rather a mineral loaded vinyl in the middle since lead is a hazardous material.


Comodave 12-08-2021 11:10 PM

1 Attachment(s)
We put the last piece in today on the access hatch in the middle of the cockpit. Will not be back to the boat until day after tomorrow since my wife has some family function tomorrow, apparently she has her priorities all wrong. Took a photo today before we put the last piece on. So far we are quite happy with how it is going.

IntoTheBlue 12-11-2021 12:18 PM

This is and always will be an interesting topic. I looked at this years ago. My boat came with a good amount of sound suppression in the engine room, however on long trips the engine noise does get to us. As explained to me, because the vibration from the engines causes the entire boat to be a sounding board (like a guitar body), suppressing the sound is not all about the engine room. Ceiling cloth, curtains, carpet underlying, etc. all help. Of course so do good engine mounts.

I own a music school in Brooklyn and we came up with the same problem in our drum practice rooms. Just impossible to stop the vibration causing the duct work to transmit the sound to the tenants above us (caused a few complaints to the landlord). We already had 2 feet of foam installed above the ceiling when we built the rooms. After some research, I found the best option was "sound absorption", not sound proofing or suppression. We ending up buying specially made floor to ceiling sound absorbing mats.
In the drum room we actually doubled them. This caused an absorbing affect and it worked. Not soundproof, but deadened the sound by absorption.

With the above in mind, I would suggest following the same mindset and use sound absorbing materials both in and around the engine room.

Enjoy!

bowball 12-11-2021 01:20 PM

Quote:

Originally Posted by IntoTheBlue (Post 1059506)
This is and always will be an interesting topic. I looked at this years ago. My boat came with a good amount of sound suppression in the engine room, however on long trips the engine noise does get to us. As explained to me, because the vibration from the engines causes the entire boat to be a sounding board (like a guitar body), suppressing the sound is not all about the engine room. Ceiling cloth, curtains, carpet underlying, etc. all help. Of course so do good engine mounts.

I own a music school in Brooklyn and we came up with the same problem in our drum practice rooms. Just impossible to stop the vibration causing the duct work to transmit the sound to the tenants above us (caused a few complaints to the landlord). We already had 2 feet of foam installed above the ceiling when we built the rooms. After some research, I found the best option was "sound absorption", not sound proofing or suppression. We ending up buying specially made floor to ceiling sound absorbing mats.
In the drum room we actually doubled them. This caused an absorbing affect and it worked. Not soundproof, but deadened the sound by absorption.

With the above in mind, I would suggest following the same mindset and use sound absorbing materials both in and around the engine room.

Enjoy!

The issue is sound is just waves that cause vibrations. Unless you decouple walls , ceilings, floors or duct works the vibrations will just transfer until enough mass or air weakens them. You need staggered decoupled walls or green glue etc.


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