Flotation chamber

[wysedav]

An enclosed space should have an inspection port to check for water and to allow everything to dry out because water will eventually find it's way in (my opinion). This is especially true when there are differential pressures involved. The main cause of the pressure differential is temp change, when the boat is out of the water and in the sun it could easily be 100F in the chamber now put it into 40F water and the air will cool off causing about a 1.5psi vacuum. SG math is correct about the loads but I think his area is too small I would be surprised if the area is less than 100in2. This could cause 150lb load on the panel which is a little more significant.

Strip kayak guys typically have large floatation chambers which are also used for storage. If they aren't vented the differential pressure can make it nearly impossible to open the hatch. I always drill a 1/16" hole as a vent so I don't have this problem , and store the boat with the hatches cracked open so it can dry out fully.

I plan on adding float chambers with access on the stripper I'm building. The panels are made from strips and are not very noticeable.

 

[ppine]

This seems like a discussion of personal tastes when it comes to flotation chambers. Waterproofed gear is going to add massively more flotation and displace a lot more water than even the best flotation chambers. For moving water, flotation needs to be added even for day trips.

 

[Canotrouge]

I must have the oddball Swift without tanks. I did see them come into being after mine was built though.

I think in canada if the boat is not plastic or wood, they are required. I heard that the first batches of Esquif Mistral didn't have them and transport canada, after testing the boat buoyancy, got Esquif to installed them( I read that some where)

 

[Mihun09]

I think in Canada if the boat is not plastic or wood, they are required. I heard that the first batches of Esquif Mistral didn't have them and transport Canada, after testing the boat buoyancy, got Esquif to installed them( I read that some where)

All the Swifts have that wedge of foam in the bottom, but it really doesn't help much with bouyancy. My Mattawa seemed to be one of the first with the integrated carbon/kevlar gunnels. It looks like they had difficulty getting it off the mold and most definitely finishing the ends, the decks are funky.

 

[madmike]

I just bought a bag of tank plugs for my Bells. (They go bad over the years.) I got them from Placid Boat Works. Just call them up.

 

[Jim Dodd]

Thanks Mike !!
Jim

 

[Iskweo]

I think the 100- 150 psi pressure estimates are pretty optimistic. Otherwise the sealed tanks on my stripper would have either imploded, exploded, or had some other catastrophic failure by now. I have seen plastic fuel containers expand in the heat but they have a much less rigid structure and of course a fuel base that expands when heated. I never seem to have any trouble getting the caps off of them when they shrink either.

I can see the benefit to using that space for storage with a trapdoor of some kind to facilitate access but I dont think I would be even the least bit concerned about pressure spikes.

 

[Philtrum]

I think the 100- 150 psi pressure estimates are pretty optimistic. Otherwise the sealed tanks on my stripper would have either imploded, exploded, or had some other catastrophic failure by now. I have seen plastic fuel containers expand in the heat but they have a much less rigid structure and of course a fuel base that expands when heated. I never seem to have any trouble getting the caps off of them when they shrink either.

I can see the benefit to using that space for storage with a trapdoor of some kind to facilitate access but I dont think I would be even the least bit concerned about pressure spikes.

Those aren't pressure estimates; they're total force estimates. E.g., 2 psi spread out over 50 square inches results in a total force of 100 pounds on the entire surface.

 

[Jim Dodd]

I'd bet a hot sunny day would create the most pressure, as I've seen plastic gas cans expand quite a bit.
I also believe venting these chambers is a good idea! I'm going to order the plugs.
Inspecting the inside is necessary.
Expecting to vent my chambers someday, they're reinforced to allow drilling, where I want to place the plug.
Again great discussion !

Jim

 

[charlie wilson]

I have seen carbon canoe tanks bulge and suck, but there is more solar gain with a black body and the whole reason for carbon is that thinner and lighter is better. I wouldn't expect strippers to deform, and one probably can't achieve a waterproof glass seal around that edge anyway. A less inclusive vent for strippers might be a 1/16" hole bored through the stripped up panel after it's glasses on both sides. I suppose a submerged hull would eventually burp the tank full of water, but we'd be dead from hypothermia or eaten by turtles long before. Curtis used little holes for years on a few thousand hulls with no adverse comments.

The leak issue seems to be from bilge water against the tanks' bottom seal. Three layers of glass strips on the bottom tank quarter instead of two helps quite a bite.

The benefit of the larger hole is getting water out. I have found leaks and water in every builders tanks. Not all but some of each. It's pretty easy to pull the stoppers, roll the boat to drain, then leave it in the sun with the tanks open for an afternoon. I'm also working on a scheme to fill the tanks with libatious spirits. Then, with an appropriate length of Tygon tube.......... The plugs allow Amber Nectar to retain it's head.

Sources for the hollow plugs would include Colden Canoe, NorthStar Canoes and Placid boatworks. They all have web sites, so no need to publish phone numbers. Remember to slit the tip, opening the hole into the tank. Also measure the stopper barrel then select the next drill bit size down. It's pretty easy to chuck a bigger bit in the drill, dang difficult to refill the hole. Kayak Drain
Plugs are available at most Paddleshops, blister packed at 2/$5 on a Sealect Designs Accessory display board.

 

[Philtrum]

Charlie, do you suppose natural cork would work? It might breathe, although that would pretty much flatten your Amber Nectar.

 

[Jim Dodd]

Just received plugs for my flotation chambers, that I purchased on ebay.
Yeah they're made in Tiawan.
A 1" hole, a couple of screws, and either epoxy, or silicone. Probably silicone.

 

[Philtrum]

Those look like transom plugs for (sail)boats. Be sure to grease the threads - they can get stuck.

 

[Jim Dodd]

Phil
Thanks for the tip !
I had a kayak paddle freeze up on me once. Lesson learned.

Jim

 

[charlie wilson]

The Sealect product does not have the heavy flange?