Engine room Sound Dampening
- Thread starter Half Wit
- Start date
The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
Comodave
Moderator Emeritus
- Joined
- Jul 2, 2015
- Messages
- 21,305
- Location
- Au Gres, MI
- Vessel Name
- Black Dog
- Vessel Make
- Formula 41PC
Welcome aboard. I have used Soundown products on several boats so far, 5 I think. Had good success with it. As a matter of fact I have two big packages of it in my garage right now waiting to go into our new Formula. No affiliation.
Keysdisease
Guru
A Vinyl/Foam composite insulation is the best performing cost effective choice for acoustic insulation. On an aft cabin boat the forward and aft bulkhead and the overhead need to be insulated with the same/same. Hull sides are very optional as noise going out the side of the vessel is rarely a problem.
Products with a 2lb barrier will provide better low frequency performance than 1lb barrier products, and just acoustic foam will provide very little reduction.
These products need to be mechanically fastened as well as adhered. Self tapping screws with fender washers for a vessel like yours are easiest. If you need to drill a pilot hole for a screw, use an awl or icepick to make the hole in the insulation, and wrap the bit in masking tape, do the same with the threads on the screws. This will keep the threads from "grabbing" the foam and creating a void behind your fastener.
Nice tight fit, as close to 100% coverage as possible. Gasketing hatches and doors if practicable, and sealing any wire and hose penetrations. For some areas just the 2lb vinyl barrier is useful. 1/4" thick and durable, for example if you have open bilges fore and aft from the ER, "hanging" this material like a curtain from the bulkhead to the hull bottom between the center stringers and slitting it to allow water flow, works very well to reduce noise traveling through the bilges.
Attention to detail will be well worth the effort considering cost and effort
There are other choices, fiberglass, mineral wool, lead, ceramic fiber, some exotic products, but vinyl foam makes the most sense.
Products with a 2lb barrier will provide better low frequency performance than 1lb barrier products, and just acoustic foam will provide very little reduction.
These products need to be mechanically fastened as well as adhered. Self tapping screws with fender washers for a vessel like yours are easiest. If you need to drill a pilot hole for a screw, use an awl or icepick to make the hole in the insulation, and wrap the bit in masking tape, do the same with the threads on the screws. This will keep the threads from "grabbing" the foam and creating a void behind your fastener.
Nice tight fit, as close to 100% coverage as possible. Gasketing hatches and doors if practicable, and sealing any wire and hose penetrations. For some areas just the 2lb vinyl barrier is useful. 1/4" thick and durable, for example if you have open bilges fore and aft from the ER, "hanging" this material like a curtain from the bulkhead to the hull bottom between the center stringers and slitting it to allow water flow, works very well to reduce noise traveling through the bilges.
Attention to detail will be well worth the effort considering cost and effort
There are other choices, fiberglass, mineral wool, lead, ceramic fiber, some exotic products, but vinyl foam makes the most sense.
Attachments
C lectric
Guru
I have the 1" Soundown foam in my boat.
It made a huge difference. My engine is right under the saloon floor so the noise came right in.. Doing the hatches first made the biggest difference. After nearly 20 yrs. I redid the hatches last year.
It made a huge difference. My engine is right under the saloon floor so the noise came right in.. Doing the hatches first made the biggest difference. After nearly 20 yrs. I redid the hatches last year.
Half Wit
Newbie
- Joined
- Nov 6, 2021
- Messages
- 3
- Vessel Name
- Wits End
- Vessel Make
- Grand Mariner
We have Teak Parquet flooring and some small carpets, not enough to provide any relief from the engine noise directly below the saloon. With the refit we are starting now we will be adding the Vinyl Foam Composite to the engine room bulkheads and ceiling, according to many it makes a world of difference. I imagine if you remove you carpet and underlay you will expose yourself to more noise and vibration with the hardwood
rgano
Guru
- Joined
- Oct 8, 2007
- Messages
- 4,995
- Location
- USA
- Vessel Name
- FROLIC
- Vessel Make
- Mainship 30 Pilot II since 2015. GB-42 1986-2015. Former Unlimited Tonnage Master
I am following a vloger who is in the process of surrounding his boat's diesel engine with 3/4-inch plywood to which he will be attaching some Sounddown. He has made it with due consideration to normal maintenance functions, and it is far less demanding of materials than blanketing the whole ER. Many generators are installed with sound boxes too.
Datenight
Guru
If you need to drill a pilot hole for a screw, use an awl or icepick to make the hole in the insulation, and wrap the bit in masking tape, do the same with the threads on the screws. This will keep the threads from "grabbing" the foam and creating a void behind your fastener.
ceramic fiber, some exotic products, but vinyl foam makes the most sense.
I also found running the driver in reverse until the screw contacts the plywood behind the insulation preventer the threads from grabbing the foam.
Rob
Keysdisease
Guru
For both hard floors and carpeted floors there are treatments that will further reduce noise. An acoustic carpet underlayment does a great job of reducing noise as well as providing a very plush feel underfoot.
For hard floors or vinyl type floors, Mass Loaded Vinyl (MLV) is a very cost effective way to get some added noise reduction.
On the subject of noise reduction, as mentioned attention to detail really adds up. Wire and hose penetrations as well as gaskets can be major sources of noise.
A very common noise source is the engine room combustion air ventilation path. This is sometimes in the wall of the cabin, the inside of a bulwark, or even in a dry stack exhaust trunk. Attention to these sources is important if you want a quiet boat
For hard floors or vinyl type floors, Mass Loaded Vinyl (MLV) is a very cost effective way to get some added noise reduction.
On the subject of noise reduction, as mentioned attention to detail really adds up. Wire and hose penetrations as well as gaskets can be major sources of noise.
A very common noise source is the engine room combustion air ventilation path. This is sometimes in the wall of the cabin, the inside of a bulwark, or even in a dry stack exhaust trunk. Attention to these sources is important if you want a quiet boat
Last edited:
rslifkin
Guru
- Joined
- Aug 20, 2019
- Messages
- 7,594
- Location
- USA
- Vessel Name
- Hour Glass
- Vessel Make
- Chris Craft 381 Catalina
It's amazing just how much noise exits via the the air vents and hull sides. It was pretty eye opening just how different things sounded (and how much louder) the first time I ran the boat up on plane in a river valley where sound from the sides could echo back.
When I got my boat , I had 79db at the helm. The helm is 4’ from a 380hp diesel. It had 2” sound down under the floor. I found a lot of noise coming through small wire runs, hatch gaskets, plumbing holes. After sealing them up and adding a nice carpet to the floor we are at 68 db. That is at 16kn with gen running. It is by far the quietest DE I have run. So after insulation go around with a db meter and look for hot spots.
