Foam bouancy

dowdy · 06 March 2011, 10:16

Just putting some ideas together before we start building on wednesday,what is everyones thoughts on filling all the underfloor voids with expanding foam,seems to big thing in states,anyone seen the ad with the boat cut in half and both bits still float?

Poly · 06 March 2011, 10:53

Dory

Nos4r2 · 06 March 2011, 10:57

Waterlogged foam

Dirk Diggler · 06 March 2011, 11:08

Boston Whaler....... underfloor bouyancy is a great idea, but you'll really regret it if you ever have to do a repair!

C-NUMB · 06 March 2011, 11:27

Only 100% closed cell foam that wont suck water in any conditions would be worth considering IMHO. But even that would add weight and cost. Don't think expanded foams fills that criteria. XPS in theory would be OK, but that can't handle polyester resin or other solvents so its not really an option.

A rib wont sink easily even if damaged so I would not do it on a rib.

Anchorhandler · 06 March 2011, 11:46

I toyed with the idea of filling all the voids on our previous boat with hundreds of ping pong type balls....admittedly you would lose some if you damaged the hull but short of ripping a big chunk out it It should of provided quite a lot of reserve bouyancy. Lightweight and cheap too (if you can source a bulk load of them, which wasn't an issue for me as we use a similar think in industrial oil separation machinery)..... It a was a French built sport fisher though

and didn't have the inherent safety of a rib. I sold the boat before I did anything about it...

Simon

Nos4r2 · 06 March 2011, 13:20

Quote:

Originally Posted by C-NUMB

Only 100% closed cell foam that wont suck water in any conditions would be worth considering IMHO. But even that would add weight and cost. Don't think expanded foams fills that criteria. XPS in theory would be OK, but that can't handle polyester resin or other solvents so its not really an option.

A rib wont sink easily even if damaged so I would not do it on a rib.

A lot of sports/fishing boats have it. It still waterlogs-it's just a matter of how long it takes.

C-NUMB · 06 March 2011, 14:39

Quote:

Originally Posted by Nos4r2

A lot of sports/fishing boats have it. It still waterlogs-it's just a matter of how long it takes.

Think we are saying the same thing. I am not aware of any PU foam that would not get water
logged by time, and then its a "no can do" situation. The foam also might to get loose from the surfaces by time, that's not funny either.

XPS believe will not get wet like EPS or PU, but can as far as I know not be used as expendable foam( + the resin issue) so guess it has not been used in marine industry that much.

martini · 06 March 2011, 20:52

My Halmatic's full of closed cell foam. Looks like it started out as 4" thick sheets which were then cut and shaped to fit in between stringers etc. When I pulled up the deck 13 years later the foam still hadn't absorbed a drop of water

dougal_22 · 08 March 2011, 14:19

my river cruiser has a foam filler between grp sandwhich lay up on the cabin roof and gun whales, granted untill i purchashed the boat it was very neglected but it has got wet and is proving an utter pain in the rear to get dry.

GordyP · 08 March 2011, 14:55

Quote:

Originally Posted by martini

My Halmatic's full of closed cell foam. Looks like it started out as 4" thick sheets which were then cut and shaped to fit in between stringers etc. When I pulled up the deck 13 years later the foam still hadn't absorbed a drop of water

+1. I was tempted to see if it would float when the tubes were removed but woosed out of the idea!

martini · 08 March 2011, 15:18

Quote:

Originally Posted by GordyP

+1. I was tempted to see if it would float when the tubes were removed but woosed out of the idea!

Mine floats with the tubes just clear of the water so I should think it will! I reckon you could puncture every chamber and tear the bottom out of the hull and it'll still get you home