I am in the process of restoring...

[Spaz]

I am in the process of restoring a 1986 23 foot Sea Ray Weekender.  I removed the rotted deck which goes from the engine compartment to the cabin. There is foam material under the deck in the area between the engine compartment forward bulkhead and the cabin the bulkhead.  Does anyone know why this is there, what is the material, and how to replace it?

[gtstang462002]

It is probably sound deadening material. Your local west marine has it available for a price that will give you a mild heart attack for the size piece that they sell. You can use pretty much any sound deadening material there as long as it is fire rated.

[Don_Mac]

It was put in for flotation

[billdillenbeck]

Flotation foam, find the cheapest rigid foam and replace it...

[burtonmd]

probably flotation, find a two part foam mix and use that, mix and pour it where needed it will rise and conform to the area that it is poured to.

[Stu2]

The foam is for flotation. When replacing it make you have water drains along the inner keel as well as water passages thru any bulkheads. Some compartments also may have drains to the bilge. You want accumulated water to flow to the bilge pump or transom drain.

[Isaacson372]

As stated above, the foam is for flotation. I replaced mine with two part expanding foam from Amazon. The foam expands somewhere around 30:1, so be careful when mixing. You can then fiberglass over the foam to finish.

[Spaz]

Thank you for the information where to buy the expanding foam.

[Spaz]

Stu and Isaacson372 Thank you for your responses. After doing some research I found it is best to use the 2 pounds per cubic foot closed cell foam. Both of you said the foam is for flotation. The information I was able to dig up is that the two part two quart system provides 75 pounds of flotation. I estimate I removed 10 to 12 cubic feet of old foam. The 23 foot Sea Ray Weekender weighs about 4000 dry. If this foam is for flotation it may be to make sure the boat will not sink to the bottom. It may also aid in sound and vibration damping because it is against the engine room bulkhead