- Joined
- Oct 20, 2002
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How much floatation do I need?
- Thread starter Thudpucker
- Start date
Interesting. I've used spray-can insulation foam, but while it works you get lots of voids and it DOES absorb some water when submerged.
One of the problems with foam in small boats is it's often in the bottom of the boat... so when flooded the boat capsizes (how often have you seen this on the news?) resulting in a boat that's very difficult for survivors to hang on to.
One of the problems with foam in small boats is it's often in the bottom of the boat... so when flooded the boat capsizes (how often have you seen this on the news?) resulting in a boat that's very difficult for survivors to hang on to.
- Joined
- Jan 1, 2000
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If you read the whole boatbuilder's handbook you will find that the rules state that the "proper" amount of flotation will not only float the boat, but float it in an upright position.
That said, not all ( small ) boats appear to do this. But, they should.
... and having "drawn" a few designs myself ( for myself. Definitely not commercial ) you are right that it is a real challenge to get all the floaty bits in the right place. The "natural tendency" is to have a big foam bottom and with all the heavy stuff on top. Which is, of course, backwards.
That said, not all ( small ) boats appear to do this. But, they should.
... and having "drawn" a few designs myself ( for myself. Definitely not commercial ) you are right that it is a real challenge to get all the floaty bits in the right place. The "natural tendency" is to have a big foam bottom and with all the heavy stuff on top. Which is, of course, backwards.
- Joined
- Sep 16, 2003
- RO Number
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The best foam is a two part liquid which litteraly explodes within minutes. You have one minute to mix and at best another one to pour.
The downside is tHat you can't remove it once it s poured so any repairs will take a lot of effort cutting it out
On the sailboat I m building I m using a lot of divinicel scraps in some compartments. I may also use cheaper foam blocks elsewhere although I don't need to archived full floatation.
The downside is tHat you can't remove it once it s poured so any repairs will take a lot of effort cutting it out
On the sailboat I m building I m using a lot of divinicel scraps in some compartments. I may also use cheaper foam blocks elsewhere although I don't need to archived full floatation.
- Joined
- Oct 20, 2002
- RO Number
- 10503
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- 3,677
One guy in Fairbanks AK, bought cases of "Touch n' Foam"!
He did his whole cabin, about 10" of foam. Roof, floor and all Walls.
He had a couple 55 Gal drums full of empty spray cans. They Explode violently when you burn them. Looked like the Fourth of July when he touched those Drums off.
A youtube showed the Foam of some sort stores water. Another said Polyethylene is the right foam.
Starting in 1979 All Mfg's of boats under 16' had to install enough foam to make a fully loaded boat float Gunnels up, and at the water level.
I still plan to build a Jon and I'll have some foam up near the Gunnels, out of the water from
He did his whole cabin, about 10" of foam. Roof, floor and all Walls.
He had a couple 55 Gal drums full of empty spray cans. They Explode violently when you burn them. Looked like the Fourth of July when he touched those Drums off.
A youtube showed the Foam of some sort stores water. Another said Polyethylene is the right foam.
Starting in 1979 All Mfg's of boats under 16' had to install enough foam to make a fully loaded boat float Gunnels up, and at the water level.
I still plan to build a Jon and I'll have some foam up near the Gunnels, out of the water from
- Joined
- Feb 28, 2003
- RO Number
- 11208
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- 428
2 part closed cell is easy to find at various retailers. it's nasty, messy stuff. whatever it touches it clings to especially clothes, shoes, etc. it will also prevent any sort of drainage in whatever space it's poured...unless you prep a little bit. line the area with plastic sheet and the plastic can be peeled away once the foam sets up. it will leave you with a custom formed foam block that is closed cell AND allows drainage, the best of both worlds.
poured foam is what leads to stringer rot in most smaller boats. once saturated, it never dries out.
poured foam is what leads to stringer rot in most smaller boats. once saturated, it never dries out.