Engine room insulation?

[Strygaldwir]

Does anyone have any recommendation for insulation material for a diesel engine room? I am refitting the insulation in my engine room and need some help finding a good acoustic, heat, and Coast Gaurd approved material. I'd love a source too!

Thanks.

Keith

[delmarrey]

I used the 1" vinyl/foam for my 50 HP diesel. Does a good job!

http://www.cyber-bridge-marine.com/soundown.htm

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[Strygaldwir]

Is it really as expensive as it appears? Can you give me an aproxamate cost for doing your engine room? Thanks, I really appreciate the information.

Keith

[CSY Man]

I used the West Marine stuff:

1/2 " of foam and something.

Works pretty good...If I had more space in the engine compartment I would have gone for the full-size 1".

Found better and cheaper stuff later at B.O.W., lead between the foam layers and all that, but again, quite happy with the W.M. solutinon.

Gave up perfection a while ago..One would always be chasing the ultimate solution and not be happy if not arriving.

Life in general and boats in particular are all compromises, therefore my $60.00 West Marine insulation is just fine.

What is important is the sea, the wind and them sunny islands, NOT the ultimate, Optimum Detail of boat one sail on to get there.

That being said, I have enjoyed picking and choosing solar panels, fridge compressors, oil filters, anchors, radios, paints, antenas, electronics, etc and all that so as to get the best and most efficient soltion overall....Yet, after $40,000 spent in the process, I am throwing in the the towel: Nothing can never be perfect, one is chasing ones tail round and round and round.....Just go sailing. I'd say.

[Strygaldwir]

I am really trying!!!

Just got to get the engine in. Figured since I have until the 12th of Jan before the engine mounting plate and engine get here, I'd make some slight improvements. That includes painting and putting new insulation in the engine room. Seems like I had a limited number of choices in insulation. Thought I get the opinion of the august body of knowledge.

Thanks for the info.

Keep sailing!

[Alan Wheeler]

I won't be able to help you with what is available to you, but I can help with what to look for. First of all, for an engine room, you need a foil liner. This does two things. It reflects heat and it stops oil from being absorbed into the foam. Both heat and oil will destroy the foam. The next part is where the expense comes in. Not all sound absorbers are created equall. The foam itself does little to absorb sound. What the trick is, is a dense layer suspended between a "mechanical isolator" which is the foam. Sound energy is transmitted through a Solid via vibration. If you can't vibrate it, it won't transmit. So in the good and Expensive absorbers, they use Barium Oxide. Usually one layer, but sometimes more. It's expensive stuff. Lead is often a poorer substitute. It is the next best material and cheaper.
The dense layer does two things. It's mass is harder to vibrate due to inertia. And two, what vibration there is, is isolated from the mounting structure via the next foam layer. The dense layer is also acousticaly dead. In other words, it is poor at resonating. So it effectivly uses up the sound energy thus stopping the sound from continueing on into the wall.
The other important point to think of. Sound is pressure. It will squeeze through holes. So all holes need to be sealed into that compartment. Air intakes need to be outside the vessel. The next point of sound travel, is transmission. It will follow anything that is connected to the source. Like the engine bed and even fuel lines and Morse cables. Rubber mount/bush as much as you can, especially when it goes through a bulkhead or deck. Large panels need to be well supported. An easy test to see what potential problems you may have is to simply bang a wall panel with your fist. The "tone" it makes in simpathy to your fist, is the tone that will be the most dominant through that panel. A really bad situation can be, that the panel is "energised" by vibration, and then resonates its own note very loudly. Thus just adding to the engine noise as if it was playing in the mechanical orchestra.
Sound is my Career and specialty. Fire ahead with any questions if you have any. If something didn't make sense, feel free to ask.

[Talbot]

An alternative approach that has been used in UK is to install a material called thinsulate:

3M™ High Performance THINSULATE™ Insulation is specified by designers for a wide variety of marine interior applications including engine rooms, overheads, bulkheads, area separation panels, and more for it’s excellent sound absorbing properties.

see Here

[Jentine]

Last fall I went to the Newport Boat Show and there was a demonstration of sound barrier. The booth operator had a small air compressor running inside an enclosed box. From the outside there was no sound. When one lifted the top, the noise was startling. The material is called "BARRIER Ultra-dB". I was very impressed with the product.

This link will give you greater information than I can.

http://www.glacierbay.com/insulation_ultradb.asp

Jim Kane

[kcrompton]

Keith,

I have always found the best sound insulation to be as air tight as possible. At least to the cabin area of course it can't be completely air tight or the engine wouldn't run. Here is a test you can do to prove my point. Get in your car and listen with all the windows up and closed off. Then barely crack one window and then you can hear all the trafic very clearly. Even then smallest hole will let sound through. Good luck!

Ken

[Alan Wheeler]

Yes Kieth, kinda correct. It also depends on what is the substance of the material making the air tight compartment though. If you were inside a large "Airtight" drum, I bet you would still hear noise, especially if I thumped it with a large hammer. A car is resonably sound proof because it also has a lot of sound absorbtion and anti-vibration proofing inside the linings. Some more than others, thus some cars have more road noise than others.
As for materials available for the purpose, there are many. Not all are created equal. Not all tests are created equal. Be very careful of some of the "test" or demonstrations performed when the product is being sold. A good box goes along way towards making that compressor or noise making device quite. Ask the guy to wrap JUST the material around the noise making device and see, or should I say, hear how good it is then. It is important to understand, that noise isolation is all about absorbing energy and changing it to something else. Heat actually. But it is so small, it is hard to measure. But the sound doesn't just stop. It is energy changed. So what ever material is used, it MUST be able to change thje sound energy, which is vibration, to something else. Thinsulate and other such materials work at only specific frequencies. They can be totally useless at low freq's, which remember, is often the very sounds you want to reduce.
The entire subject of sound is extremely simple, yet unbelievibly complex. It is the very essence of physics and takes in all of the laws of physics. You can't bend or break the laws of Physics. But you sure can baffle the audiance with claims of what products will do. So make sure, what ever product you get, you get all the Test data of that product. It will come(it should come) with a STI rating. That is a "Sound Transmission index". This will tell you what frequency is absorbed by how much with what level of insulation. If someone can't give you those figures, be vary wary of any claims.

[Strygaldwir]

Thanks everyone for the information. It has been very helpful. I got a product that is a quilted lead fiberglass composite. It is three inches or so thick and something like 2lbs per square foot. It has 4 layers. there is a layer of insulating fiberglass followed by a layer of very stiff lead impregnated foil or something, followed by another layer of fiberglass then finally a vapor/liquid repelling layer. This layer is not foil, it is a black quilted material.

I got fiberglass because it has a better fire rating than Vinyl. It does not smoke when it is subjected to high heat. It meets Coast Guard large vessel materials standards, for whatever that is worth?

This is very close to the material that is installed in the other hull, just looks a little thicker. I can't hear that engine from the wheel, I have to go bellow and I can just bearly hear the engine when it is running. If I had not been looking at the gauges when I started the engine, I would have had no clue it was running! If I can get close to that, I will be happy. Given what this stuff cost!!$$# I better do at least as good.

I will provide an update when I get the engine in and running.

Thanks all.

Keith

[Strygaldwir]

An update. It is very difficult to tell if there is any difference so far in the noise level between the old and new engines. I think there are a couple of issues going on though. The first is the new 3YM30 is quieter than the old 3GM30. This I can tell by opening the engine hatches and listening to both engines.

The old insullation may be slightly better than the new insullation. I think this is due to the fact that I have not yet plugged all the access holes in the new installation. In the old, all wires and access to the engine compartment are through PVC conduit and then the whole conduit is sealed with a silcone plug. Heck to get out, but definatly worth doing. When I have finished everything in the engine room I'll replug the conduits also.

From the helm station, I still can't tell if the engines are on at idle, so I am happy! Poorer but happy.

Thanks for the tips all.

Keith

[cat man do]

Has any one heard of or tried this product?

Silent Running

An easy way to reduce sound and unwanted vibration aboard
Featuring easy application and excellent adhesion to a variety of surfaces, this high-performance viscoelastic coating is an easy way to reduce unwanted noise and vibration aboard. Use it on or around virtually any source of unwanted noise or vibration, including the hull, stringers, engine beds, bulkheads, ceilings, hatches, engine boxes and bow thrusters. Can be used on all surfaces, including fiberglass, aluminum, and steel. Water-based, non-toxic and VOC free. USCG approved.

• Base Formulation: Water-based acrylic
• Recommended Application Method: Brush, roller, spray
• Number of Coats Recommended: Minimum 4 coats @ 10mil./ coat (40mil. minimum thickness required at full cure)
• Drying Time: To touch: 1hr.; overcoating: 1hr.
• Drying Time to Full Cure: 5-7 days (required for full noise and vibration attenuation)
• Coverage: 40sq. ft./gal. @ 40mil. (10 mil/coat)
• Thinner: Not recommended
• Color: Off-white
• Clean Up: Soap and water

We have a mob over here saying it's the best stuff around, of course , their selling it, and it would be easier to install than foam/barium insulation, but would it work.

This is being sold by West marine for all you Northern Hemisphere guys.

Dave

[Alan Wheeler]

About 15yrs ago, a product kinda similar came out. It was a little thick to brush on and I think it was more a trowel on product, but my memory is foggy on that. Anyway's, it was design mostly for steel and Aluminium hulls to stop noise through the hull. Epsecially wave slap. It worked well, but was expensive as it didn't go far being so thick. It was also an acrylic water based product and similar colour. I wonder if it is the same stuff, but maybe watered down slightly to enable it top go further and make it easier to apply.

[Zach]

When it comes to insulating around engines... I feel that it is best to do 90% of the surface at the level of overkill... and leave the last 10% with less.

It is disconcerting when the motor is running, and the noise/vibration is such that you cannot get in tune to the vibration to tell if something is wrong. If you can't tell the motor is running, how can you tell if it just threw the belt... shredded the impeller and is blowing steam?

Low frequency stuff goes through the stringers to anything that isnt perfectly assembled. A few pads on the cabinet doors can do wonders... when they are what sing! Any thin plywood needs to have cross bracing glued to the back... if the whole panel is vibrating it is moving air, making sound. Keep a panel from moving, or absorb the motion... one is cheaper than the other.

You would be amazed what you can do with concrete board, lead sheeting and asphault tiles. The solution does not have to be heavy... if you take the plastic sheet behind the door panel of a car door off, the door clangs. With the plastic sheet... the air doesnt move, so the panel doesnt.

Just remember gauges are helpful, but your ears and toes work best!