filling or leveling of bilge

[bertie]

i am restoring a bertram 28 and the bilge has a keelson? or reverse keel running the length of the boat. it creates an area that is almost impossible to keep dry. because of the gaps on either side. i would like to fill this in and level it out. wondering what material is best to use. foam? thickened epoxy?.....

[jimslade]

Thickened epoxy will work fine. Stay away from foam, it will absorb water

[Tim B]

Keep to the resin system you started with. The epoxy manufacturers will always claim that there's no problem coating polyester in epoxy, but if you then glue a strip across a hull side that's epoxy at one end and polyester on the other, which should you use and where will it fail?

Anyway....
Foam is reasonably good for packing out large volumes for little weight, but make sure it is well-covered (coat it with resin before it goes in if you want).

I have used expanding foam with a layer of chopped-strand mat and quite a bit of resin before, that worked quite well, but be careful when shaping it with a wire brush on a drill (pretty much the only way). The dust goes EVERYWHERE.

Alternatively how about using Balsa to pack out the volume if you're not looking at huge spaces?

Thickened epoxy is only really viable for filleting or filling small spaces in a non-structural manner (somebody will disagree with that, I know it...). It is also heavier and more expensive than foam or balsa.

Tim B.