Commodores:
This weekend while working on the 38, I saw a couple of opportunities to improve the boat. First, in the Vee-berth is a space between the "beaver board" and the hull where I could put in some insulation when I take the old beaver board out and replace it with mohogony. Has anyone done this? The concept would be to cut down on the sweating on the hull and, hence, the mold and mildew elements. The second is in the engine and afterdeck rooms. A PO put in pink fiberglass insulation about 2 inches thick between the deck and the beaver board
with holes in it. This paneling is held up with 1 X 1 pieces screwed into the cross stringers. Of course the beaver board is sagging after all these years. I have a picture of this restoration thread. It would be good to sound proof, to what ever degree possible, the ceiling in the engine room. High tech soundproofing material on the internet is expensive, and I don't want to use egg cartons. Styrefoam could be a possibility, but it burns and melts pretty fast. I suspect whatever the solution, it will be a job to put in place. Now is a good time to get it done, once we get the engines out and the whole place pressure sprayed and vacumed out. Advice, experience and wisdom are appreciated!
Jerry

Jerry,

I would avoid the fiberglass insulation, it will get into everything. Small specks of glass will blow around in the motor compartment, it will get into the cabin, and you guys will have the equivalent of "itching powder" all over the boat.

Personally, I don't think insulation works on a boat. We have not had any condensation in ours summer or winter, because we ventilate the boat in the summer, and keep heat on in the winter. Somehow it works for us, and we have zero mildew, and this is in Alabama where it gets very humid in the summertime.

I have found little need for acoustic insulation, because the exhaust note is so pronounced there is no point in trying to isolate the motor noise, which is generally unnoticed. My advice is to save your energy and money for something else.

Howard,
Huntsville, AL



howard at howardechols@hotmail.com

Hi Jerry,
Quite a project you have going on. I have a 38 as well. I have just got around to ordering some soundproofing insulation for Bonaventure (Paul referenced my boat earlier in your original post)last week. I have wanted to put it in my engine compartment for quite awhile. I find the engine noise travels up through the plywood overhead in the side lockers and right out through the locker doors. I ordered 2" foam with a vinyl boise barrier sanwiched between 2 1" pieces faced with the reinforced silver mylar. That is for the over head outboard of the hatches and forward of the hatches. I also ordered the 1 ' for the aft bulkhead. Forward bulkhead will have to wait until next year. Here is a link to the company I purchased from http://www.soundown.com/

I will post some pictures when I get going on the job.

Good luck on your project.

George

Here's the thread on George's fine looking 38, BONAVENTURE. He took it to extremes, and had the hull painted like a new Hatteras Yacht. Some people have all the fun!

http://www.network54.com/Forum/424840/message/1145912019/

Regarding the insulation, I agree with the comments about using fiberglass batt insulation, and would not do it. If there are areas of sound deadening like George mentioned, the specialty products will do the job.

I'd wait to see how much noise you have, before thinking too much about sound deadening.

I don't have any insulation in our 38, and we have not seen any condensation inside the hull summer or winter. We do keep the heat on in the winter, sometimes to the tune of $100 per month, but we also spend a lot of time there after work, week ends, etc., too.

Regards,

Paul

George:
Bonaventure looks great! The paint job is first class. My hatches are all in poor shape and each one for a different reason. They will take some doing to meet your quality and standard of finish. You and Paul's experiences and advice are well heeded. I notice the sound travels the same way in mine and there are a multitude of holes drilled through the bulkheads and in the cabinet doors for ventilation. Howard's comment is right on too with regard to just how much volume can be surpressed. I anxiously await your evaluation. I did find another sound dampening manufactoring company and will have to try to look it up. I believe it was a company called Kodiac. Not cheap! They were promoting a sandwich version with 4 layers of different density foams, different sheets of foil, and a dense composit. Vibration is a huge componant, but with explosions in the cylinders, volume is too. Each company touts its products using different measures of supression and I have not scaled that learning curve yet. I do think from my carpentry knowledge that if I were to use aerosol foam from the small cans to seal cracks, holes and air spaces that a certain amount of smalltime noise can be contained. Maybe not absorbed, but contained. I am referring to where electrical wires go through bulkheads (or went through at one time) and the like. I will stick out my neck and say that a wooden box, covered with lead foil on the inside, and built around the motor would quiet those big beasts considerably. It would be a big job to engineer one and probably not worth the effort. I will save my money until we hear from you!
Jerry