rafiki_
Well-known member
Any experience out there with sound deadening? I am thinking of a pad above the 2 engines mounted to the base of the engine room hatch. Any views on the viability and what to use?
Engine noise reduction
- Thread starter rafiki_
- Start date
tinkicker0
New member
enterprise
New member
Insulation
There is usually a guy selling sound insulation foams at the boat jumbles, these are good quality insullation, the engine bay stuff is usually coated with a fire resitant foil.
Looking at your location I would sudgest a trip to Malvern boat jumble in February or a trip (although not been as good for a while) Gloucester Jumble in March (or April, not sure).
There is usually a guy selling sound insulation foams at the boat jumbles, these are good quality insullation, the engine bay stuff is usually coated with a fire resitant foil.
Looking at your location I would sudgest a trip to Malvern boat jumble in February or a trip (although not been as good for a while) Gloucester Jumble in March (or April, not sure).
Mr Googler
Well-known member
Noise Killer
I used this stuff
http://www.noisekiller.co.uk/marine_soundproofing_products.asp
Its not cheap but very good.
They say its designed to cut out the specific frequencies in a marine application
I had 2 diesel v8's rattling around in a very empty engine bay. It was extremely noisy
but this stuff did the trick. Remember to seal the edges between sheets and this also makes alot of difference.
I used this stuff
http://www.noisekiller.co.uk/marine_soundproofing_products.asp
Its not cheap but very good.
They say its designed to cut out the specific frequencies in a marine application
I had 2 diesel v8's rattling around in a very empty engine bay. It was extremely noisy
but this stuff did the trick. Remember to seal the edges between sheets and this also makes alot of difference.
VicS
Well-known member
Noise control is a highly specialised topic.
There are two aspects to consider. the use of sound deadening materials which prevent the transmission of noise by the surrounding structures and the use of sound absorbing materials.
You would do well to seek proper qualified advice or you could simply be wasting money and achieving very little
There are two aspects to consider. the use of sound deadening materials which prevent the transmission of noise by the surrounding structures and the use of sound absorbing materials.
You would do well to seek proper qualified advice or you could simply be wasting money and achieving very little
rafiki_
Well-known member
Sound advice (sorry for the pun), but it is airborn noise I want to reduce. It is not a disaster at the moment, but I would like to take a couple of dB's off from 1000 t0 2000 revs. Engine noise not a big feature above these revs as other noises take over.
Tranona
Well-known member
Halyard Marine www.Halyard.eu.com are the experts on the subject. Vetus www.vetus.co.uk also sell a range and have information on pp190/1 of their catalogue.
russ
Active member
I was taken out on boat today that i am thinking of buying but my one concern was the engine noise from the KAD32 diesel and the scream from the turbo when throttling up to full power.
Would sound deadening take the dbs down enough?
Would sound deadening take the dbs down enough?
jfm
Well-known member
Rafiki
From the boats I've experineced before/after it makes a worthwhile difference if done well. However it wont work if you just cover the underside of the engine room hatch. You must cover the whole of the surface twixt engine rom and passanger space (ie the whole deckhead on a medium sized boat). If you leave any gaps, the sound gets thru. Imagine you're outside a room in which there is a loud party, and the door is closed, muting the sound. As soon as you open the door an inch or two you can pretty much hear everything. Opening the door the rest of the way, till it's wide open, hardly makes any further difference. So you have to cover the whole surface, not leave any "door ajar" uncovered bits
BartW
Well-known member
there are 3 points to take care about
1) you must make sure there are no holes or gaps in the hatch or cover, a small hole from a lock, a gap between the hatch, some rubber strip missing etc. as Jfm say's, every small gap is a source of noice.
2) you should "damp" the hatch or cover plate with a "heavy foil" sort of material, such as the rubber as is used inside the door of a car, It is the weight of this material that will "isolate" the sound, you need weight to be able to isolate, and this "dead" material will die the vibrations of the plate where it is fixed at, otherwise the cove plate will vibrate and act as a loudspeaker.
3) you need to absorb the sound inside the engine bay, by a foam type of material, just to damp the noise already at the source.
the materials from 2) and 3) you can find them combined in some special purpose material as offered specifically for this application, as shown in previous reply's.
You have to look that it is made of different layers, some more heavy, some more foam type...
if you take care of these 3 points, and threat the cover or hatch of the engine bay as much as possible with this material, you will certainly note a big difference.
(my company is in Professional sound and acoustics
)
1) you must make sure there are no holes or gaps in the hatch or cover, a small hole from a lock, a gap between the hatch, some rubber strip missing etc. as Jfm say's, every small gap is a source of noice.
2) you should "damp" the hatch or cover plate with a "heavy foil" sort of material, such as the rubber as is used inside the door of a car, It is the weight of this material that will "isolate" the sound, you need weight to be able to isolate, and this "dead" material will die the vibrations of the plate where it is fixed at, otherwise the cove plate will vibrate and act as a loudspeaker.
3) you need to absorb the sound inside the engine bay, by a foam type of material, just to damp the noise already at the source.
the materials from 2) and 3) you can find them combined in some special purpose material as offered specifically for this application, as shown in previous reply's.
You have to look that it is made of different layers, some more heavy, some more foam type...
if you take care of these 3 points, and threat the cover or hatch of the engine bay as much as possible with this material, you will certainly note a big difference.
(my company is in Professional sound and acoustics
)
segaerta
New member
My last winter project was sound insulating my engine room.
I chose Merford. It was a good alternative to more expensive products from Vetus, based on the fact sheets. Don't know if it is sold in the UK. It comes in Merfocom (no deadening) and Merfocell (deadening).
I did the entire engine room, covered up all walls and ceilings. Let no spots uncovered. Hell of a job due to tight spots. Took me about three days to get it all done (37 ft cruiser) but then, I'm not used to this kind of hard work
It definitely did the job since noise levels are a lot lower now than they were before, but can't tell by how much since I did not do any db readings before and after. However, I still feel noise levels should be lower but I guess in an open sportscruiser that is not easily done.
Good luck,
Alain
I chose Merford. It was a good alternative to more expensive products from Vetus, based on the fact sheets. Don't know if it is sold in the UK. It comes in Merfocom (no deadening) and Merfocell (deadening).
I did the entire engine room, covered up all walls and ceilings. Let no spots uncovered. Hell of a job due to tight spots. Took me about three days to get it all done (37 ft cruiser) but then, I'm not used to this kind of hard work
It definitely did the job since noise levels are a lot lower now than they were before, but can't tell by how much since I did not do any db readings before and after. However, I still feel noise levels should be lower but I guess in an open sportscruiser that is not easily done.
Good luck,
Alain
MapisM
Well-known member
No experience at all - my boat is already extremely quiet and doesn't need that.
I guess that thick wood is very effective in this respect.
But what you're envisaging is exactly what they did in the following boat.
According to its review, the result is a boat "quieter than a church on Monday".
PM me if you're interested to know more.
jfm
Well-known member
That's the one where they put a soundproof box around the engine, as well as insulating the engine room, right Mapis? A trawler yacht, though I've forgotten which
(Separately, I was away over the holidays and didnt see the forum much. I just saw your reply alluding to -I think- Seat Pagine Gialle etc
Shall we assume that thread is dead or do you want a reply?!)
MapisM
Well-known member
Yep, a 62' custom steel trawler, based on Bruce Roberts design.
The main engine (single) is fully enclosed in the box shown in the previous pic.
Re. SPG and that thread, ermm.... which thread?
The main engine (single) is fully enclosed in the box shown in the previous pic.
Re. SPG and that thread, ermm.... which thread?
rafiki_
Well-known member
BartW, are you part of LMS? Though not an NVH engineer myself, I have run many programmes where LMS software has been used with great success on vehicle programmes.
I am going to treat this issue in stages
First stage seal the hatches and use deadening material on the hatch undersides. If I still have a problem then I will look at engine mounts etc.
I am going to treat this issue in stages
First stage seal the hatches and use deadening material on the hatch undersides. If I still have a problem then I will look at engine mounts etc.
Tallulah
New member
Insulation
I did quite a lot of work on my P50 using 3M products. Princess are/were working with 3M and use some 3M products as standard on their production boats including an excellent and very thin/reasonably light, under carpet product (not sure what it is but I guess Princess or 3M would help here). I then retro fitted 3M "thinsulate". This is another 3M product that is used for both thermal and acoustic applications. I lined my saloon (behind all the cabinet work and seating and above the ceiling panels. I also obtained some of their fireproof thinsulate and lined the roof of the engine compartment. The result was a 3-6dB drop (depending on where you measured) in sound levels in the saloon - a huge difference. The biggest difference was where the saloon table is bolted through the floor (it's electric rise and fall) as it was acting as a microphone above the D12's just below and tranmitting sound directly into the saloon. The fireproof thinsulate over the base in the engine room dealt most effectively with this. The additional benefits are that thinsulate is VERY light and adds significantly to thermal insulation so my eberspachers do not need to work so hard. I also used 3M tape around the hatches to the engine room as even the smallest gap with spill noise.
I've tried to find a link to suppliers but can only find refernces from the USA. Worth a look though as you get big results withouth lots of added weight.
Brian
I did quite a lot of work on my P50 using 3M products. Princess are/were working with 3M and use some 3M products as standard on their production boats including an excellent and very thin/reasonably light, under carpet product (not sure what it is but I guess Princess or 3M would help here). I then retro fitted 3M "thinsulate". This is another 3M product that is used for both thermal and acoustic applications. I lined my saloon (behind all the cabinet work and seating and above the ceiling panels. I also obtained some of their fireproof thinsulate and lined the roof of the engine compartment. The result was a 3-6dB drop (depending on where you measured) in sound levels in the saloon - a huge difference. The biggest difference was where the saloon table is bolted through the floor (it's electric rise and fall) as it was acting as a microphone above the D12's just below and tranmitting sound directly into the saloon. The fireproof thinsulate over the base in the engine room dealt most effectively with this. The additional benefits are that thinsulate is VERY light and adds significantly to thermal insulation so my eberspachers do not need to work so hard. I also used 3M tape around the hatches to the engine room as even the smallest gap with spill noise.
I've tried to find a link to suppliers but can only find refernces from the USA. Worth a look though as you get big results withouth lots of added weight.
Brian
BartW
Well-known member
no, I'm not part of LMS, but know of them.
we are specialised in pro audio equipment sales and installation for studio's, broadcast and theatre's,
and do some acoustic designs as a side activity.
we use:
"Roomtools" for measurements
and "Ease" for simulating the electro acoustics
http://www.amptec.be/references
good idea to start with the dead sheet
best regards
Bart
BartW
Well-known member
no comments on the 3M product Thinsulate, no personal experience myself, but heard good thinks of it. Especially as extra temp isolation, and improving the acoustics (reduce reflections of sound) of your saloon, I believe this does a good job.
But,
if you really want to isolate the noise coming from the engine you need "weight". this is pure fysics,
you cant isolate noise without adding more weight,
I now this is not what we want in our planing boats, but the more we want to isolate noise, the more weight we have to add.
There are some clever solutions, but still they need some addition of weight !
3db less noise you will "notice"
6db less noice you will "notice very well"
if you want to acheeve that the average person has the feeling the noise is reduced 50% you need 10 db reduction.
so if you threat the roof of the engine compartment and hatches with 3 of 4 mm rubber (eventually the thinsulate on top of it)
and make sure that openings from table stands etc are firmly closed,
airtight with GRP, wood +Rubber, or Silicon, (foam nor thinsulate is no good for that)
you would get some substantial extra noise reduction
Trundlebug
Active member
Just my two-penneth, I bought some sound deadening pads from a boat jumble last year. They were approx. 1.5mx1m x35mm, foil faced, good quality from a supplier that does all the trade shows.
I stuck it on to the underside of the engine hatches using Evo Stick "Sticks like S**t" (Yes, really, that's what it's called) and, despite predictions of doom and gloom from various quarters who said "you have to use 2-part adhesive, nothing else will do" it's been absolutely fine and quite effective, although not a huge difference as it was merely replacing old insulation of similar thickness but not as dense.
It has made the hatches heavier to lift though..
In summary, if you're looking to buy sound insulation panels, think about buying it from boat jumbles - it's not only 2nd hand stuff for sale. There are some great bargains to be had, and as this stuff isn't cheap, some big savings can be made without compromising quality.
It's also the right time to be buying, as the boat jumble season is starting now.
I stuck it on to the underside of the engine hatches using Evo Stick "Sticks like S**t" (Yes, really, that's what it's called) and, despite predictions of doom and gloom from various quarters who said "you have to use 2-part adhesive, nothing else will do" it's been absolutely fine and quite effective, although not a huge difference as it was merely replacing old insulation of similar thickness but not as dense.
It has made the hatches heavier to lift though..
In summary, if you're looking to buy sound insulation panels, think about buying it from boat jumbles - it's not only 2nd hand stuff for sale. There are some great bargains to be had, and as this stuff isn't cheap, some big savings can be made without compromising quality.
It's also the right time to be buying, as the boat jumble season is starting now.
PCUK
Well-known member
The first thing to do is to seal all openings especially the hatch surrounds. If there are no hatch seals then fitting proper seals around the hatches will do all you want to achieve without any further work. If you want to go further then use a lead lined sound deadening material.
