More on Foam Flotation.

Post by **CSMarine** » June 10th, 2004, 8:01 am

I've heard a lot of different opinions on the advantages and disadvantages of using two part foam when restoring/rebuilding a boat. Some say you are highly prone to delamination of exsisting fiberglass. I've heard all kinda advice on both sides. I'm not talking new boats now. Just project boats.

I'm rebuilding a boat now. Turning a run-about into a flats boat. Floors were rotted. I've removed the cap, and pulled up the deck. Most of it was dripping wet and rotted out bad. Underneath the deck was two part foam. The panels were actually holding water in the lower part of the compartments, but the foam was still firm and dry. I've heard of closed cell foam holding water, but this foam was in, as new condition. It was injected in 1989. I've also heard of using foam shipping peanuts in plastic bags. These are just laid in the panels before sealing in the deck. Cheap, but effective.

Anyone have any ideas on boat floation?

Post by **Tom Keels** » June 10th, 2004, 9:24 am

I've seen some of the folks on the boat building sites talk about using empty 2 liter bottles to fill the big voids and then use the 2 part foam over them thereby keeping the weight down and saving on the cost of the foam. Seems like a sound idea.

Post by **Chalk** » June 10th, 2004, 9:27 am

Like I already told you...if you have water leaking into a compartment and no means of draining, it will cause rot and delaminating. That is why I told you I was pouring my foam inside plastic lined bays. If water gets into compartment it must be allowed to drain out. If it is allowed to drain and water gets in there it should leave, if it doesn't, rot and delaminating can occur.

#1 rule of boat building (according to me) prepare for water intrusion, plan for it and compensate for it (maintenance planning).

Saying a compartment is water tight and full of foam and won't rot is like saying Marine Corp gear won't tear up in the hands of a Marine. It just don't go together

You could just put a bunch of coke bottles in there too

with the cap on

Post by **wevans** » June 10th, 2004, 10:04 am

HUMMMMMMM, a boat full of COKE

could make things interesting

Post by **CSMarine** » June 10th, 2004, 10:56 am

I'm mostly concerned about delamination of fiberglass that is old, has already been wet for a while (bilge area). I'm not talking prestine new boat wood or glass.
The idea with the two liter bottles is a good one Tom. Air weighs less than foam, so it would be a good filler for the large areas. Anyone ever used CPES? (Clear Penetrating Epoxy Sealer)

Post by **Eerman** » June 10th, 2004, 5:58 pm

I know absolutely jack sh** about boat building so this may be a stupid statement. But don't shipping peanuts dissolve in water. So, if you got water in there somehow and the plastic bags they're in aren't absolutely water tight...isn't that a problem. Probably just came off sounding like an idiot; but, I'm used to it.

Post by **CSMarine** » June 16th, 2004, 8:32 am

Eerman, just read your reply. I put a handful in a bucket of water for a week, and they didn't waterlog. I'm more concerned about the effects of bilge water on the peanuts. That's why I've discounted using them.

Post by **Chalk** » June 16th, 2004, 8:43 am

Take a piece or wood or something and put on top of them and force them under water. That would be a true test of how they would react. But you would have to weigh them before the testing and then after words to see if they absorbed any water.

Alot of work when they sell two part foam for boat building by the gallon

Plus gas believe it or not usually ends up in the gray water, which means that it could come in contact with your "nutz" and we all know what gas does to styrofoam....