Originally Posted by skoolie_n00bie
... closed cell insulation would be the best noise reducing material...
I think for the purposes you are interested in, the type of "closed cell" foam that might work for you would be the kind they make sleeping bag pads out of. They are amazing at keeping the cold at bay. I have one on the floor right now to cut the cold. When temps are staying at freezing or below, my floor is cold. It cuts the cold so much that one of my kids (who freezes even in summer) could sit on the floor and temps were dropping into single digits.
I bought some 28" x 72" sleeping bag pads from Wal-Mart. One was $8 (14 sf= about $0.57/sf) and one was $15 ($1.07/sf). The more expensive one is what my kid was sitting on. I have a piece of the cheaper one in front of the shower that I put my shower floor towel on (it soaks up the water when I step out of the shower). Breaks the cold as well as the more expensive pad. It's not as soft and cushy though. Works so well that I'm thinking of using it (the cheaper $8 one) in the stairwell and (the softer $15 one) on the exterior of the engine cover. The softer pad will also become liners for my rugs. At 6 ft, the soft pad runs the length of the salon and will do the same in the galley. I'm going to make a machine washable envelope style "rug" for each of the pads (I bought a new sewing machine). Soft pad with soft rugs.
I will glue the $8 pad to the metal sides and steps then cover the foam with a hard material (probably the same flooring material I put on the walls plus I need to use some PVC wood to attach the hard material to the metal... thermal break that won't rot). For the engine cover, I will use regular engine liner and put the softer, more flexible $15 pad on the exterior of the engine cover, using either spray glue or contact cement to stick it down, then glue a vinyl over the foam. That's my thoughts right now. I may find something better/affordable or not.
Upside to the sleeping bag foam is I can just buy a couple pads at a time at the local Wal-Mart. I don't have to worry about ordering too much or too little. If I come up a little short, Wal-Mart is just 7 miles away.
Flooring on the walls and sleeping bag pads on the engine. What a combination. Works for me and that's all that matters. This may or may not be the best solution. But since I no longer sleep much, I just lay awake thinking and thinking of things to do on the bus is less emotional and more productive.