When is flotation not flotation?

[MrPlywood]

re: seat tanks taking on water - I realize that adding the noodles is basically insurance, as well as offering the opportunity to remove any previously installed, waterlogged foam. My boat did not have any foam in the tanks. I guess I could have repaired the seat tank joints all around, but I'm not that familiar with glassing and i imagine that the material costs would have been similar if not more. The time spent certainly would have been more for me.

re: noodle buoyancy - it occurred to me while I was cutting the noodles to length, that I could also have cut them in half lengthwise, and in quarters if I was really ambitious. Either way would allow tighter packing with fewer voids than going with the stock noodles. And if I was REALLY ambitious I could add 4" ports in the rear of the tanks to allow for even tighter packing. As it is I got 30 in each tank, and could fit more into each, but decided to put some under the gunwales for now. I think they will be more effective at helping right the boat. I lose a little storage space (paddles and drink cans) but I think it's worth it.

re: self-righting DS1 - I think this 1975 article was linked to previously, but here it is again. It talks about how adding flotation under the gunwales made a big difference in righting. It also mentions creating flotation areas under the transom. I have some foam billets used for dock flotation that I plan to try to carve into shape and place in that area.

http://www.arlingtonyachtclub.org/Fleet ... ation.html

Is all this overkill? Maybe, but as Phill put so succinctly "Please rig for worst case and you won't have to explain why you didn't. "

[kokko]

I think adding flotation under the gunwales is a great idea. Easy too. I think I will buy some 2" closed-cell foam and adhere it under the gunwales, transom and cuddy deck.

I have also been considering a flotation panel for the main. Here's a link

http://www.saillavieusa.com/covers.htm

They are hellishly overpriced, and I haven't seen them available elsewhere. On my local lake a lot of the scow and cat sailors use them. The idea is it will keep the mast afloat so the boat will not turtle. It is similar to the idea of mounting float on the top of the mast like Hunter does on their daysailors.

[kokko]

I do know that my mast has foam flotation, but I assume that is in the same condition as the foam I pulled from the seats - useless as flotation

[MrPlywood]

Maybe the guy making the sheetbags in this thread

http://forum.daysailer.org/forum/viewtopic.php?t=3354

could quote on the flotation panel idea...

[GreenLake]

I've gone over the numbers and I think 95 is a scare scenario based on some glitch in the math. I get closer to 35 for neutral buoyancy, see here:

http://daysailer.org/forum/viewtopic.php?p=15026#15026

[ctenidae]

I've gone over the numbers and I think 95 is a scare scenario based on some glitch in the math. I get closer to 35 for neutral buoyancy, see here:

http://daysailer.org/forum/viewtopic.php?p=15026#15026

My math sucks. I redid it, and got the same answer as you. Not sure how I got such a small factor for the volume- can't recreate it at all.

[K.C. Walker]

This topic gets a lot of discussion and traffic. Something I've noticed and wondered about is why the integrity of the flotation tanks themselves are not much discussed. It seems to me it's sort of like making sure that the shutters work on the castle but not worrying about the castle wall. I mean, once the horde is inside the castle wall you've got big problems. One can never get as much flotation out of foam as you can from a well sealed tank.

Cape Cod shipbuilding recommends no flotation foam but to make sure that the tanks are well sealed. They offer a service for testing and resealing older flotation tanks which seems like a good idea to me. Anybody have any idea how they do this? I'm asking because it seems like it shouldn't be too hard as a do-it-yourself operation, I would think.

I wonder what the best method of checking the integrity of the flotation tanks would be. If I capsized I would far prefer not having water in my flotation tanks and having to worry about whether there is enough foam. I suppose one could put some low pressure air in the tanks and then spray soapy water all over them.

When I overhauled my boat during my "core project", I did find cracks along the forward bulkhead where it met the hull that makes the flotation tank and also along the keelson which is connected to that tank. I didn't find any around to seat tanks, though. I did however find a crack in the hull underneath my starboard tank and that tank was damp.

Flotation foam inside the tanks it's definitely belt and suspenders.