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  Topic Review (Newest First)
06-11-2011 05:43 PM
SJ34 I like the idea of watertight compartments. If you need to use the space it's there.
06-11-2011 04:17 PM
WDS123 Regarding positive flotation in a smallmkeel boat - all the Schock Harbor 20s since approx. Hull 130 have foam flotation. We install 22 cubic feet of foam in a 1,800 disp. boat. We have a 6 ft bow tank.

It required a surprising amount of calculation and testing to get the location of the foam correct.

We found that one needs to be careful when cutting and inserting the foam to make certain to try and prevent the foam from chipping. Instead of a knife, we use a heated wire to cut the foam - it seals by melting the foam.

Also, select a foam that will not under any circumstance absorb water. We did extensive long term (30 & 60 day) immersion testing of closed cell foams and discovered some closed cell foams would absorb a minscule amount of water, this might lead to nasty molds and smells.

We heat shrink the foam blocks to seal them. We considered applying resin or gel coat as a sealant ( we have plenty of those materials around ), but decided on heat shrink wrapping the foam.

I agree that one should carefully consider wherenin the boat the foam is placed, ideally if the boat swamps it floats more are less level.

One should also consider the weight of the crew and the weight of the gear in the boat.

Finally, I think you might also consider glassing in air tanks with inspection ports similar to dinghies. If a DIY has enough experience, it should be easy enough to do.
05-26-2011 11:19 PM
Originally Posted by Windkiller View Post
I understand the pros of floatation
What are the Cons of installing floatation? besides space issues
Space is the big issue and a distant second is weight in the ends.
05-26-2011 07:39 PM
SVPrairieRose No thats not my boat its a skipjack I believe. Port browning is on pender island. A great pub, and marina. No snobbery.
05-26-2011 07:36 PM
Windkiller I understand the pros of floatation
What are the Cons of installing floatation? besides space issues
05-26-2011 02:01 AM
Windkiller ps is your picture a picture of your boat, that's a fine looking gaff schooner
Where's Port Browning?, I'll have to look that up
05-26-2011 01:39 AM
Windkiller Hahaha from this link here Floatation values
It looks like I'd need about 300-400 2 litre pop bottles..If I drink that much pop I might not need flotation anyway (I'd need a dentist!)..or a boat, I could just sail the pop bottle raft..
I guess I should clarify, I'm looking for flotation that'll fit inside my boat!!
05-25-2011 11:21 PM
SVPrairieRose Empty pop bottles! If they can build an island they can float a boat. Come by Port Browning when your done and show it off.
05-25-2011 09:38 PM
SJ34 Several pros and cons for flotation but if your gonna do it why not use polystyrene? It's much lighter and cheaper than the expanding polyurethane foams. You could fill most of the voids with polystyrene blocks then make up the rest of the volume with the expanding foam. Just a thought.

50lbs at the ends of an 18' boat will contribute to pitching motion.
05-25-2011 07:55 PM
Windkiller Funny!
My mutineer 15 dinghy has floatation and it's somewhat comforting to know that short of hitting a mine or being blown up somehow I'll likely stay afloat
I've heard that as the sailboat gets larger it stops being space effective because of the huge amount of floatation required
Any more opinions out there?
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