Reply
 
Thread Tools Display Modes
 
Old 07-25-2013, 10:25 PM   #1
Senior Member
 
AussieCraig's Avatar
 
City: Fulton TX
Country: USA
Vessel Name: The Salty Swallow - named by wife
Vessel Model: Private builder - 50' Trawler
Join Date: May 2013
Posts: 179
Engine noise insulation

I am seriously considering 'boxing in' both the 671 and the generator with a wooden frame and some sound insulation...I did a search and read what was already on the site but decided to see if anyone had any recent updates on what is available as far as sound deadening panels or other ideas to cut the transference of engine noise to the cabin...

There is a foil faced sheet of some sort of insulation already lining the roof of the engine room however some further reduction would be great....anyones experiences would be appreciated !
__________________
Advertisement

__________________
Craig 'Aussie' White
'Not all who wander are lost...'

AussieCraig is offline   Reply With Quote
Old 07-25-2013, 10:50 PM   #2
Enigma
 
RT Firefly's Avatar
 
City: Slicker?
Country: Bumpkin?
Join Date: Oct 2007
Posts: 9,995
Greetings,
Mr. AC. Even not knowing the layout of your ER, I would be hesitant to "box in" a piece of machinery that I would have to access on a daily basis (fluid checks, repairs, emergency actions etc.). Might you be better to increase the engine roof soundproofing?
__________________

__________________
RTF
RT Firefly is online now   Reply With Quote
Old 07-25-2013, 11:20 PM   #3
Guru
 
AusCan's Avatar
 
City: Adelaide
Country: Australia
Vessel Name: Kokanee
Vessel Model: Cuddles 30 Pilot House Motor Sailer
Join Date: Jul 2012
Posts: 2,095
Hi Craig,
I've got the same project on my to-do list. It appears most of the effective noise reduction panels have a thin sheet of lead or similar in them. The mass is required to absorb the low end frequencies. There are spray on products, although I am not sold on them.
It appears any decent material is fairly expensive (and heavy). About $80 (and 10 lbs) for a 3ft x 4ft sheet from our local marine suppliers.

It is also very important to ensure your hatches are well fitted. A small gap can transfer a lot of noise.

Besides reduced access as RTF mentioned; boxing in an engine too much may cause overheating issues.
AusCan is offline   Reply With Quote
Old 07-26-2013, 01:34 AM   #4
Senior Member
 
AussieCraig's Avatar
 
City: Fulton TX
Country: USA
Vessel Name: The Salty Swallow - named by wife
Vessel Model: Private builder - 50' Trawler
Join Date: May 2013
Posts: 179
I should have elaborated a bit, the boxing in would entail panels that could be lifted off and away giving full access to the engines. I agree with you Auscan, it appears you get what you pay for and it won't be cheap....
__________________
Craig 'Aussie' White
'Not all who wander are lost...'

AussieCraig is offline   Reply With Quote
Old 07-26-2013, 02:49 AM   #5
Guru
 
BruceK's Avatar
 
Join Date: Oct 2011
Posts: 7,564
Most genset makers offer a sound shield, which suggests it is ok to have one,which you could replicate DIY. Depending what the original costs.
Boxing in the main engine sounds more problematic, but think of older boats where the engine protruded into the saloon and a box over it became a table. Recently we were in Scotland aboard a converted trawler with a boxed over engine in the cockpit. Even so, heat dissipation must be an issue, and if you vent the box you`ve got noise.
__________________
BruceK
Island Gypsy 36 Europa "Doriana"
Sydney Australia
BruceK is offline   Reply With Quote
Old 07-26-2013, 11:43 AM   #6
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,707
Engines have mufflers on them usually on the exhaust only. Take the air cleaner off your car and you'll experience a lot of intake noise. Especially when you "stick your foot in it". On a diesel engine there is no throttle valve to shut out the intake noise at low throttle openings as the intake tract is always wide open.

Some marine engines have next to no intake muffling hardware. So it seems to me that large reductions in noise, especially right above the engine/s (like the main salon in one's boat) would be at least worth thinking about.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 07-26-2013, 01:00 PM   #7
Guru
 
skipperdude's Avatar
 
City: Whittier AK
Country: USA
Vessel Name: Apache II
Vessel Model: 1974 Donald Jones
Join Date: Oct 2007
Posts: 3,147
You need to check with the engine manufacturer to determine how many cubic feet of air the engine requires.
4 3" diameter holes was enough air for my cat 3208.

You will need to vent the box. A fan to suck the heat out more than likely.

Better to insulate the overhead. Go in the ER and turn off all the lights where you see light coming in sound gets out.

SD
__________________
If you can't repair it maybe it shouldn't be on the boat
skipperdude is offline   Reply With Quote
Old 07-26-2013, 01:23 PM   #8
Guru
 
Phil Fill's Avatar
 
City: Everett Wa
Country: US
Vessel Name: Eagle
Vessel Model: Roughwater 58 pilot house
Join Date: Oct 2007
Posts: 2,919
I would not enclose the engine but sound proof the engine room and or better muffled exhaust system. Being The Eagle engine room is pack with stuff that absorbs noise, the engine room is carpeted, a new improved muffle exhaust, and the salon is carpeted it a lot quieter than when we original bought the boat.

There are ways quiet the engines.
Phil Fill is offline   Reply With Quote
Old 07-26-2013, 02:55 PM   #9
THD
Guru
 
City: Seattle
Country: US
Join Date: Apr 2012
Posts: 1,142
Have a friend with a single 671 and he had a "sound blanket". heavy sound suppressing material, suspended on wires just over and around the engine, perhaps 8-10 inches. I was never convinced it did a lot of good, but he claimed it made a measurable difference. Since he is an engineering type-I take his word for it.
THD is offline   Reply With Quote
Old 07-26-2013, 03:39 PM   #10
TF Site Team
 
Larry M's Avatar
 
City: JAX, FL
Country: USA
Vessel Name: Hobo
Vessel Model: Krogen 42-120
Join Date: Nov 2008
Posts: 5,729
We have a factory built sound shield on our generator. The service points are all on one side so only one panel needs to be removed for routine service/inspections. The air intake is a baffled so the sound reflects off of the sound deadening material. For quick checks such as oil and the water pump, there are 2-4" inspection plates. Our sound shield does what it is suppose to.
Larry M is offline   Reply With Quote
Old 07-26-2013, 09:55 PM   #11
Guru
 
Nomad Willy's Avatar
 
City: Concrete Washington State
Country: USA
Vessel Name: Willy
Vessel Model: Willard Nomad 30'
Join Date: Oct 2007
Posts: 13,707
In the old days w my 17' OB cruiser I started out one morning and after it warmed up I took off my coat. A rather large coat. I looked around for someplace to throw it and saw the engine back there humming away. I threw the coat over the engine and was amazed at how quiet it suddenly became. I ran a lot after that w that coat over the engine .. a 35hp Johnson.
__________________
Eric

North Western Washington State USA
Nomad Willy is offline   Reply With Quote
Old 07-27-2013, 12:30 AM   #12
Guru
 
HopCar's Avatar


 
City: Miami Florida
Vessel Name: Possum
Vessel Model: Ellis 28
Join Date: Aug 2011
Posts: 3,501
I'm sure these folks make what you need.
Soundown (Sound Down, sound down, sounddown) - The Woldwide Leader in Noise Control Engineering
I used their 1" foam with a loaded vinyl barrier (similar to lead) to line my engine box and hatches. It helps.
I usually talk to their Ft. Lauderdale office. Very nice people to deal with.
HopCar is offline   Reply With Quote
Old 07-27-2013, 01:05 AM   #13
Senior Member
 
City: Hong Kong
Country: Hong Kong
Join Date: Nov 2012
Posts: 210
There is also the magical cork panels, light weight, cheap and can be coated with noise reducing coats like Mascoat Delta Db. Can be glued onto existing insulation, onto the fuel tanks, the engine bed and hull. This will be a cheap solution.

Reducing engine vibrations to the hull is also important - Isoflex engine mounts (Australian as far as I know) makes specialized mounts and they are reasonble in price.
Searios is offline   Reply With Quote
Old 07-27-2013, 12:02 PM   #14
Guru
 
Aquabelle's Avatar
 
City: sydney
Country: australia
Vessel Name: Aquabelle
Vessel Model: Ocean Alexander Flushdeck
Join Date: Jun 2012
Posts: 537
I'd recommend Sounddown..as noted in post #12. You might consider their acoustic carpet underlay as a first step if you have a carpeted salon...otherwise if you have inadequate ER lining, pull out and use the heaviest Sounddown panels you can afford.
Aquabelle is offline   Reply With Quote
Old 07-27-2013, 02:13 PM   #15
Senior Member
 
City: Hong Kong
Country: Hong Kong
Join Date: Nov 2012
Posts: 210
Sounddown is good - no question about that.

But, 6mm of cork would reduce the sound with 10-15 Db as per some experts. That's a lot of sound reduction for very little thickness. Or maybe add 6 mm more for even better result. It is glued onto the existing surfaces / existing insulation and will therefore be a much easier fix compared to replacing or adding Sounddown, which probably would require a lot of equipment to be removed before the Sounddown can be installed.
The carpet underlay is a good idea though and would probably be first on my list.
Searios is offline   Reply With Quote
Old 07-27-2013, 03:22 PM   #16
Senior Member
 
AussieCraig's Avatar
 
City: Fulton TX
Country: USA
Vessel Name: The Salty Swallow - named by wife
Vessel Model: Private builder - 50' Trawler
Join Date: May 2013
Posts: 179
Quote:
Originally Posted by Searios View Post
There is also the magical cork panels, light weight, cheap and can be coated with noise reducing coats like Mascoat Delta Db. Can be glued onto existing insulation, onto the fuel tanks, the engine bed and hull. This will be a cheap solution.

Reducing engine vibrations to the hull is also important - Isoflex engine mounts (Australian as far as I know) makes specialized mounts and they are reasonble in price.
Excellent points, the air intake for the 671 is an uninsulated metal pipe so some lagging around that would help and I will check the engine mounts - from memory they may be solid...

There are also many reflective surfaces in the ER itself that could be insulated...and cork stick ons may do the trick...
__________________
Craig 'Aussie' White
'Not all who wander are lost...'

AussieCraig is offline   Reply With Quote
Old 07-27-2013, 03:33 PM   #17
Senior Member
 
AussieCraig's Avatar
 
City: Fulton TX
Country: USA
Vessel Name: The Salty Swallow - named by wife
Vessel Model: Private builder - 50' Trawler
Join Date: May 2013
Posts: 179
@ Aquabelle and Searios, I will be replacing the carpet with sheet flooring asap so underlay will be part of that job. I will also see if I can find some 'cheap' cork tile to attach to the existing ER roof insulation....I will take some pics and report on the effectiveness once done...
__________________
Craig 'Aussie' White
'Not all who wander are lost...'

AussieCraig is offline   Reply With Quote
Old 07-27-2013, 03:38 PM   #18
Senior Member
 
AussieCraig's Avatar
 
City: Fulton TX
Country: USA
Vessel Name: The Salty Swallow - named by wife
Vessel Model: Private builder - 50' Trawler
Join Date: May 2013
Posts: 179
Found this stuff too that might go on the ER roof before the cork....

2mm Rubber Underlayment 16 dB Acoustical Sound Control 4'x25' Flooring Rolls 100 Sqft - Amazon.com
__________________
Craig 'Aussie' White
'Not all who wander are lost...'

AussieCraig is offline   Reply With Quote
Old 07-27-2013, 10:00 PM   #19
Senior Member
 
City: Hong Kong
Country: Hong Kong
Join Date: Nov 2012
Posts: 210
Cork rolls are preferable to cork tiles - but not so easy to get and more difficult to handle -

I'm using 6mm cork rolls glued onto the underside of my floors, facing the bilges. This should give better insulation, reduce possible sweating of the floor steel stringers and also reduce wave slapping noise (I hope)...

I might even add cork on my floor over the engine room as well.
Searios is offline   Reply With Quote
Old 07-28-2013, 01:38 AM   #20
Senior Member
 
City: Hong Kong
Country: Hong Kong
Join Date: Nov 2012
Posts: 210
The idea to carpet the engine room floor is a good one - reduces noise, eases the pain on the knees and knuckles, tools and bits stay put if the boat is rolling and it absorbs smaller amounts of water or fuel before it goes into the bilge.

I will consider that on my boat.
__________________

Searios is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off





All times are GMT -5. The time now is 08:10 AM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012