Hi Ho
Veteran Member
Looking to reduce the engine noise in the main cabin where the diesel engine is located beneath the cabin sole. What soundproofing material did you use and are you pleased with the results? Thanks for your input.
Soundproofing
- Thread starter Hi Ho
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Comodave
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I have used Soundown on several boats. Happy with the product.
caltexflanc
Guru
First order of business is to look for sources of vibration and mitigate, including the condition of the engine mounts.
I agree Soundown has great products, but getting to some of the root causes comes first. They can advise you on that as well, pretty much one stop shopping.
https://soundown.com/marine-noise-control/
I agree Soundown has great products, but getting to some of the root causes comes first. They can advise you on that as well, pretty much one stop shopping.
https://soundown.com/marine-noise-control/
markpierce
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This isn't about a specific product, but more a general tip. Sound can come out tiny cracks. Like how if you open a window just a tiny bit, the outside sounds become much more noticeable.
If you put a running shop vac in your engine room and then use some sort of db meter (maybe one on a phone these days) you can move it around and find those cracks that are letting sound pass through. If you are not sure, even tape can change it so you can try that to see if you have your leak spots sussed. Then concentrate on trying to seal/block them.
This can be done after doing the Soundown too, to find any little missed gaps or cracks.
If you put a running shop vac in your engine room and then use some sort of db meter (maybe one on a phone these days) you can move it around and find those cracks that are letting sound pass through. If you are not sure, even tape can change it so you can try that to see if you have your leak spots sussed. Then concentrate on trying to seal/block them.
This can be done after doing the Soundown too, to find any little missed gaps or cracks.
C lectric
Guru
I used the Soundown 1" loaded foam and it mad a BIG difference.
I agree about the small leaks, that they can allow a lot of noise energy to bypass the best of intentions.
I remember still when my wife waked about the salon I could tell when she stepped on a hatch. The noise dropped considerably. Her weight, being carefull here, was enough to seal the gaps at the hatches before I did the Soundown.
I agree about the small leaks, that they can allow a lot of noise energy to bypass the best of intentions.
I remember still when my wife waked about the salon I could tell when she stepped on a hatch. The noise dropped considerably. Her weight, being carefull here, was enough to seal the gaps at the hatches before I did the Soundown.
Keysdisease
Guru
Reducing noise is often the sum of several treatments. As Frosty and others have said, small leaks around hatches are the most cost effective reduction you can get. A hatch without a gasket can leak 5-10Db which can be reduced for $10 - $20.
If you have a downstairs station the cable and hose path from the engine room to the console is also a source of noise, the conduit to the flybrigde station if you have one, penetrations of the bulkheads for plumbing and wires, as are any combustion air paths that may abut accommodation spaces.
As mentioned a vinyl (todays lead) foam insulation as thick and heavy as you can fit will be the main treatment in most cases. If your salon is carpeted an acoustic carpet underlayment usually works very well. With all airborne products, a major rule: If it doesn't weigh much, it won't do much
And as caltexflanc mentioned, engine mounts as well as the way your exhaust is supported can be noise sources. Exhaust hard supported to the overhead or glassed through a bulkhead can be a noise source.
Listen to your boat to find sources. On a quiet morning start her up and poke your head in various places to determine noise sources and paths, start with the easiest / least expensive treatments first, and work your way through treatments until you are happy with the result.
If you have a downstairs station the cable and hose path from the engine room to the console is also a source of noise, the conduit to the flybrigde station if you have one, penetrations of the bulkheads for plumbing and wires, as are any combustion air paths that may abut accommodation spaces.
As mentioned a vinyl (todays lead) foam insulation as thick and heavy as you can fit will be the main treatment in most cases. If your salon is carpeted an acoustic carpet underlayment usually works very well. With all airborne products, a major rule: If it doesn't weigh much, it won't do much
And as caltexflanc mentioned, engine mounts as well as the way your exhaust is supported can be noise sources. Exhaust hard supported to the overhead or glassed through a bulkhead can be a noise source.
Listen to your boat to find sources. On a quiet morning start her up and poke your head in various places to determine noise sources and paths, start with the easiest / least expensive treatments first, and work your way through treatments until you are happy with the result.
Hi Ho
Veteran Member
Thanks for the responses. I know I have a lot of air leaks and some places that will be very challenging to get insulation in place. Presently all I have is the old acoustical tiles and areas where it was removed when the fuel tanks were replaced and air conditioning installed.
Certainly I need to work on the air leaks but concerned some might be impossible and will the extra insulation be for not.
Certainly I need to work on the air leaks but concerned some might be impossible and will the extra insulation be for not.
ScottC
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Hi Hi Ho,
Keysdisease mentioned an "accoustic carpet underlayment" earlier in this discussion.
I am writing here to let you know that, if you are using carpeting, you can, indeed, achieve excellent results with this strategy. It happened to me quite by accident. My boat came with an insulated cocoon around the 165hp turbo diesel and was, in my estimation, fairly quite inside when operating on diesel. After about 7 years of ownership, I decided to replace the carpet...because it needed replacing. The carpet warehouse I was dealing with had DENSE ~5/8" inch rubber matting on the concrete floor in their customer service area, where workers are standing most of the day. I noticed this and asked about it because I thought it might be nice to have something like this under the carpeting at the helm, where I spend hours standing. So, I installed some at the helm and it felt soooo good to stand on, that I decided to put it under the entire (wall to wall) carpet in the main salon (which is over the engine). After this, I noticed that the diesel noise was reduced by ~20-30%. What a pleasant surprise!
Here is a website where you can see a bit more about the rubber matting I'm referring to. Sorry, it's in Swedish, but the picture and specs may help. Perhaps you can paste some text into Google translate? The key words seem to be anti-fatigue. A lot of "anti-fatigue" mats come up when searching for US sources, but in all varieties, including "honeycomb", which you would not want. So, I thought it best if you can at least see what I'm talking about in this link.
https://matthuset.se/product/mattor...lus-ergonomisk-avlastningsmatta-pa-metervara/
Keysdisease mentioned an "accoustic carpet underlayment" earlier in this discussion.
I am writing here to let you know that, if you are using carpeting, you can, indeed, achieve excellent results with this strategy. It happened to me quite by accident. My boat came with an insulated cocoon around the 165hp turbo diesel and was, in my estimation, fairly quite inside when operating on diesel. After about 7 years of ownership, I decided to replace the carpet...because it needed replacing. The carpet warehouse I was dealing with had DENSE ~5/8" inch rubber matting on the concrete floor in their customer service area, where workers are standing most of the day. I noticed this and asked about it because I thought it might be nice to have something like this under the carpeting at the helm, where I spend hours standing. So, I installed some at the helm and it felt soooo good to stand on, that I decided to put it under the entire (wall to wall) carpet in the main salon (which is over the engine). After this, I noticed that the diesel noise was reduced by ~20-30%. What a pleasant surprise!
Here is a website where you can see a bit more about the rubber matting I'm referring to. Sorry, it's in Swedish, but the picture and specs may help. Perhaps you can paste some text into Google translate? The key words seem to be anti-fatigue. A lot of "anti-fatigue" mats come up when searching for US sources, but in all varieties, including "honeycomb", which you would not want. So, I thought it best if you can at least see what I'm talking about in this link.
https://matthuset.se/product/mattor...lus-ergonomisk-avlastningsmatta-pa-metervara/
Last edited:
ranger58sb
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We replaced our original carpet with new premium and with the heavier Soundown underneath. That made some difference in sound, and it also gave the flooring much more cushion.
-Chris
-Chris
C lectric
Guru
Any insulation will help reduce noise. It may not be as effective with any leaks or missed areas but it will be better than otherwise.
I have the same situation, some openings that would require dismantling part of the boat to gain access to close and some areas that I never did cover.
Soundown also offers a noise reducing carpet underlay. Check their site out in addition to the suggestion from ScottC.
From my own experience tackle the hatches above the engine first.
Compared to many mine are lightweight but regardless the foam made the biggest single difference right there. Pay attention to the gaps around the hatches also as they will leak noise.
I have the same situation, some openings that would require dismantling part of the boat to gain access to close and some areas that I never did cover.
Soundown also offers a noise reducing carpet underlay. Check their site out in addition to the suggestion from ScottC.
From my own experience tackle the hatches above the engine first.
Compared to many mine are lightweight but regardless the foam made the biggest single difference right there. Pay attention to the gaps around the hatches also as they will leak noise.
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Marco Flamingo
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I have been looking at addressing some of the "breaches" in my soundproofing caused by prior owners. One installed a diesel heater in the engine room and cut a couple of odd shaped 8" holes (one handed with a sawzall demolition blade?) for the 3" heat duct. There are other similar penetrations in the ER soundproofing that are way larger than needed. One of the goofy openings is into the undersink cabinet in the head. The head is so noisy that when the door is open it is the largest source of engine room noise in the main cabin.
Large holes like the sawzall problem will require some handiwork. But I'm tempted to try canned foam for smaller areas. I have the gun type of foamer that can touch up little areas and penetrations without having to use up the entire can in one go. It isn't a soundproof foam per se, but a little dab of foam would definitely be an improvement over an open area between the ER and living space. And it can be easily torn out if whatever is passing through the soundproof bulkhead needs to be removed. Plus, using a foam gun is fun.
Large holes like the sawzall problem will require some handiwork. But I'm tempted to try canned foam for smaller areas. I have the gun type of foamer that can touch up little areas and penetrations without having to use up the entire can in one go. It isn't a soundproof foam per se, but a little dab of foam would definitely be an improvement over an open area between the ER and living space. And it can be easily torn out if whatever is passing through the soundproof bulkhead needs to be removed. Plus, using a foam gun is fun.
HiHo, I recall there were some previous threads over the years about acoustic insulation and they were very helpful.
I used to have those (likely similar) acoustic tiles in my old boat. They were really designed to reduced reflected noise but were basically useless for sound reduction. If yours are all solid and attached firmly then you could go directly over them with mass loaded vinyl, otherwise it’s going to be a “fun” job scraping them off.
But it will be worth it in the end.
Keysdisease
Guru
Makobuilders is right on about what acoustic tiles do and don't. And his MLV suggestion is also on target.
The canned foam is easy and tempting, but because it has no mass it will only reduce higher frequency noise.
Mass loaded vinyl is the current industry standard noise barrier. It replaced lead for a variety of reasons, price and toxicity being just two. 1lb a sq ft of lead and 1lb sq ft of mass loaded vinyl will perform the same for noise unless you have very sensitive instruments and want to split hairs at various frequencies.
Mass Loaded Vinyl (MLV) is pretty cheap, looks and acts like a "rubber sheet," cuts with scissors or a razor knife, plays nice with just about any adhesive, and can be screwed, nailed and stapled, and..., its a noise barrier.
As with any noise reduction product, more is better. 1lb is more readily available, 2 layers will perform like 2lb sq ft MLV. This has more to do with frequency than anything else, 2lb reduces lower frequency better.
Maybe use the foam to fill the gaps, cut any excess off to make it flush, then cut some MLV to attach around the opening. Slit it to go around the pipe and offset the slit with a second layer.
Lowes, Home depot, hundreds of online sources.
The canned foam is easy and tempting, but because it has no mass it will only reduce higher frequency noise.
Mass loaded vinyl is the current industry standard noise barrier. It replaced lead for a variety of reasons, price and toxicity being just two. 1lb a sq ft of lead and 1lb sq ft of mass loaded vinyl will perform the same for noise unless you have very sensitive instruments and want to split hairs at various frequencies.
Mass Loaded Vinyl (MLV) is pretty cheap, looks and acts like a "rubber sheet," cuts with scissors or a razor knife, plays nice with just about any adhesive, and can be screwed, nailed and stapled, and..., its a noise barrier.
As with any noise reduction product, more is better. 1lb is more readily available, 2 layers will perform like 2lb sq ft MLV. This has more to do with frequency than anything else, 2lb reduces lower frequency better.
Maybe use the foam to fill the gaps, cut any excess off to make it flush, then cut some MLV to attach around the opening. Slit it to go around the pipe and offset the slit with a second layer.
Lowes, Home depot, hundreds of online sources.
Hi Ho
Veteran Member
The air leaks are going to be my biggest challenge in some areas because of lack of access. Just saw a YouTube on putty pads around electric boxes a pipe, looks interesting. For the bigger area's like the framing around the fuel tanks I wonder if ridged foil faced mineral wool board might be a solution. Certainly my hatch gaskets have seen better days!
Datenight
Guru
Maybe use the foam to fill the gaps, cut any excess off to make it flush, then cut some MLV to attach around the opening. Slit it to go around the pipe and offset the slit with a second layer.
socool:[/QUOTE]
Exactly what I was going to suggest with the foam. It will give you good backing for the MLV.
Rob
socool:[/QUOTE]
Exactly what I was going to suggest with the foam. It will give you good backing for the MLV.
Rob
Keysdisease
Guru
For some penetrations that have irregular gaps, one technique that works well is a combination of foam and Dyna-Mat.
Dyna-Mat is an automotive product used to dampen sheet metal. Makes your Pinto door sound like a Mercedes. But it has mass and is self adhesive.
Like for a wire bundle going through a bulkhead or the overhead to a console. Try and tiewrap the bundle above and below the penetration to make it as uniform as possible. Try and leave it a little loose in case someone needs to pull a wire in the future. Where the bundle penetrates stuff foam in all the gaps and then 1 wrap around the bundle just before the penetration. Now take the sheet of Dyna-Mat and wrap it around the foam that's around the bundle and mash it against the bulkhead. The foam around the bundle is just there to protect the bundle from the very aggressive adhesive of the Dyna-Mat.
This works very well, is inexpensive and easy. If you ever need to take it apart shears or a razor knife will open it right up.
You want to do all this on the side where the noise is, always try to address noise as close to the source as possible
Dyna-Mat is an automotive product used to dampen sheet metal. Makes your Pinto door sound like a Mercedes. But it has mass and is self adhesive.
Like for a wire bundle going through a bulkhead or the overhead to a console. Try and tiewrap the bundle above and below the penetration to make it as uniform as possible. Try and leave it a little loose in case someone needs to pull a wire in the future. Where the bundle penetrates stuff foam in all the gaps and then 1 wrap around the bundle just before the penetration. Now take the sheet of Dyna-Mat and wrap it around the foam that's around the bundle and mash it against the bulkhead. The foam around the bundle is just there to protect the bundle from the very aggressive adhesive of the Dyna-Mat.
This works very well, is inexpensive and easy. If you ever need to take it apart shears or a razor knife will open it right up.
You want to do all this on the side where the noise is, always try to address noise as close to the source as possible
