Expanded foam for flotation

[susqeyaker]

just got a manta ray 14 and it has a dip in the hull on the bottom between the first and second scupper holes. when i load it on the racks it deforms where the pads contact the yak much more than my manta ray 12. was thinking of foam as a way to make it a little more rigid. has anyone done this? what type of foam did you use?

[tufnik]

I too didn't think I needed internal floatation. When I inadvertently flipped my Trident, the hatch was loosely on. Water seeped in slowly, then rapidly. It was nearly submerged. Ever try to upright a water-filled yak? Nearly impossible. I eventually got help though.

The Trident did not come with internal floatation. I would put foam in because you'll never know when you're going to flip and if that hatch is really on securely or water-tight at the instant you flip.

[john from md]

Some years ago I bought two part foam from a company on the web. Sorry, I don't recall their name. I called them to ask about my intended use, ( under floor boat) and to make sure it was not hygroscopic.

These folks were very helpful and, from what I recall, the process was easy and the measuring was such that I only had small areas to trim out. It does not react as fast as the urethane stuff they make for sealing windows and doors. I do remember I felt it was expensive though for the amount I needed.

I would think that those of you who have kayaks with two large hatches, can fill some of the insides with pool noodles. From what I have seen of SOT fishing yaks, people tend to keep their gear topside, unlike SINK rec yaks where you tend to store your stuff inside.

I plan to add pool noodles to mine even though I don't plan to carry more than two rods and a small tackle box when I fish. To me, buoyancy in boats is like fuel and altitude in aircraft; you can never have too much.

John

[Yak Fish]

Hobie Models 2011 and up come with inner floatation foam just like you're saying. Mine has two long rectangles on both sides that make it virtually unsinkable. In addition, I put my outriggers inside there fully inflated for whenever I may need them. So you guys could get inflatable type bladders that don't take up any room when they are deflated. I store a lot of stuff inside the kayak so I wouldn't want any kind of permanant solution.

If you want foam, make sure it's closed cell so that it doesn't eventually become a sponge. Spray foam seems like a bit of an unneeded mess and hard to figure out how much you need and have used. I don't think you really need that much floatation. Just calculate the weight of the kayak and figure out the equal weight of water you need to displace...that's the dimension of foam to use...plus some margin.

To support 100lbs you'll need roughly need 2 rectangles of foam 6" x 6" x 42".
Stuff them in the side walls and forget about them. Or that's roughly 2 pool noodles about 5.5 feet long.

[ictalurus]

I've had one kayak sink underneath me and had another get quite a lot of water in it (15 or 20 gallons). Sinking isn't the issue. The real problem is that the kayak becomes unstable as more water enters the hull. If the hole/leak is big, it becomes unstable really fast. I don't think any amount of internal floatation will prevent this unless you fill the entire interior with foam/floats so there's no room for water. Where the floatation will help is keeping the kayak floating after it's flipped, which should make it easier for your rescuers to find you and possible give you something to get part of your body out of the water to slow down hypothermia.

[Southerly]

too unstable to sit in is probly very accurate and good point to keep in mind.

regardless, i like idea of flotation to possibly prevent the loss of $$$ for all the gear, but also to make locating the kayak user easier, if you're far from shore for example. might want to desert the kayak, but maybe not - but having options is a good thing if you are able to make sensible decisions.

but i strongly suggest testing your foam to make sure it does not absorb water prior to using in your yak, and also being careful that too much expansion does not damage your hull.

i had a windsurf board got dinged and absorbed water. without exaggeration - just like a sponge and impossible to dry out again for all practical purposes.

that home insulation sheet foam from home depot - either the blue or pink board (not the white pellet stuff) does not absorb water. you could cut pieces of this to fit in hull, then glue the pieces together to make a form-lock shape. just an idea.

i have some pool noodles in mine but am pretty sure it's still a sinker presently due to amount of gear when fully rigged. i'l probably just add a couple more noodles when kmart re-stocks. the only problem is finding places that don't interfere with rudder control cables inside of the hull or compromise gear-carrying.

[nay_sayer]

The center of my kayak is filled with expanding foam (done by the manufacturer for extra rigidity since it was a display model) and it works fine. The foam doesn't hold or soak up water. I'm not saying do it to yours, just adding my two cents.

[Southerly]

i've noted there are a bunch of different expanding foams. high expansion and low expansion from home depot. and boat catalogs (maybe defender for example) offer a couple different formulations - the reason i suggest testing for water absorption before putting in yak.

when i saw how much water the foam of a 'surfboard' can hold, it was an eye-opener. in hindsight; it was probably a lightweigh version of foam and cell walls of the bubbles were not 100%

[tufnik]

Anyone think about using well-placed plastic bottles in the yak? (e.g., clorox jugs, juice containers, soda bottles, etc.)

[ronaultmtd]

Too noisy for me and too much weight- use pool noodles