Spray foam insulation as yak flotation?

I want to add additional flotation to my OT Loon 111 and I’m thinking of using some “Great Stuff” spray foam insulation to do so. Normally used for household insulation, it’s Pro’s are low cost and (I hope) ease of installation. It’s a closed cell foam that should work … my plan is to alternately stand the yak upright on its bow and stern ends and to then spray the foam until it fill up a reasonable amount of that end - maybe 12-18" or so. In an 11’ foot boat I’m compromising footroom & storage space for flotation, so I’ve got a tradeoff to balance.

So, I’d like to know if anyone else has tried such and if so, how well did it work? Other key things like - did it react and/or dissolve the hull material (OT’s Polylink 3 in my case)?

Speaking of Polylink 3 … OT says it’s foam core provides flotation … imho that’s half accurate. Full of water it rides just below the surface - yeah, it doesn’t sink to the bottom but it doesn’t exactly float either. It’s kind of like a submarine that achieves perfect depth balance, lol!

spray foam
I seen a few spray foam jobs, and none of them have held up long term. Most of those foams will absorb water and break down eventually.

If I were in your shoes I would either go with removable tapered float bags or toss a mesh bag filled with cut-up foam noodles from Wal-mart.

Barring that, you could glue/velcro a cheap foam sleeping pad to the underside of your decks. Just make sure you can remove the things eventually.

If you don’t want to compromise storage
space, an alternative would be to get two large dry bags and stuff them with flotable material – and stow them in the bow and stern. And make sure they are straped in so they won’t float away in the event of a capsize.

When you need storage, remove the fluff and put your clothing (or what ever) in the dry bags and roll them up good. They will still give you flotation.

Now if the foam blocks are in the way, maybe you can use two smaller dry bags on each side of the foam block.

go for tapered float bags
eve4n with maximal floatation self rescue in big rec boats is dodgy. anything is better than nothing and anything works on a pond (if the water is warm)but…

BTW rumor has it you can deform a boat if you put in too much foam and develop pressure on the hull.

west marine
west marine has a marine version of that it is kind of expensive but it should hold up better than spray foam you should check it out

spray foam breaks down real easy and wouldn’t last

No No no No!!!
Just get some float bags and tie them into the boat. They don’t compromise storage as you can deflate them as much as needed to make room for your stuff.

If you bought your kayak new and they didn’t try to get you to buy float bags then shame on them! A kayak needs float bags, a paddle and a PFD to go with it. Float bags or at least dry bags should be part of the package!

Absolutely not!
It will breakdown/crush/crack and absorb water.

It will be hell to remove.

It can warp the hull.

It’s a sticky mess to work with.

You’ll need so many cans you could have just bought good float bags for same money.

If you’re looking for a fast way to destroy a kayak go ahead, otherwise follow the other suggestions.

Don’t bother
Issue#1 with “great stuff” is that its not meant for big closed-in spaces. it’ll remain gooey in the center for a very long time and the density won’t be even with some big ass hollow spots and some goo that will eventually harden. There are places that sell 2 part foams which is what you really wanna use if you’re set on foam. And yes, you’d need probably 10+ cans to provide any amount of floatation.

Why don’t you go the normal way and get drybags? or floatation bags? theyre dirt cheap.

As to Great Stuff warping plastic…it’s greatly exxagerated unless you do it in extreme heat.

Glad I asked …
What a great forum! Thanks to all who replied … it’s obvious from your remarks that “great stuff” is NOT the way to go, lol.

The dry bags suggestions are good, I just bought 3 for my wife and I and I think that’s the way I’ll go - until I can find a good deal on some tapered flotation bags - I may find that the bags alone will do fine. The cheap mesh bags filled with packing noodles is also an idea that appeals to me (especially the miser in me).

As a guy who’s chronically afflicted with the “I can do that!” disease - characterized by the capacity to leap before looking - I’m so glad I asked this forum before I just went ahead and did it. Thanks again for saving me from myself! [sheepish grin]


PS - RE dry bags, having never purchased a true dry bag before, last month I bought a set of 3 bags from Sams Club. While the smallest bag was a true dry bag, the two large bags were like duffel bags with zippered flap-style top lids - as I found out the hard way, these bags were not “dry bags” but “splashproof” bags [Yep, I dumped it in about 6’ of river]. To Sam’s Club credit, they took the bags back sans receipt with only a perfunctory Q&A session. Lesson learned, the 3 bags I just bought are true dry bags.

Yeah those dufflebags…i’ve seen that style of bag at walmart with a ‘waterproof’ on the tag and went " yeah okay…its going to leak like a sieve through that zipper".

Have you looked at the inflatable tapered dry bags? like this http://www.mec.ca/Products/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524442617472&FOLDER%3C%3Efolder_id=2534374302700593&bmUID=1147035299534 i am sure other brands make em too. not cheap but very versatile.

nay sayers r us

– Last Updated: May-07-06 6:20 PM EST –

i wonder how many of the posters have any actual experience using expanding foam as an end pour. there's a lot of puristism around here. i have used it successfully BUT i still agree you would probably be happier with float bags.

No, I’ve never done it - but I really don’t think that takes much away from the validity of stating the obvious drawbacks.

I have used it in construction and home repair. I can connect the dots…

You don’t have to get them
at Walmart

You don’t have to actually shoot

– Last Updated: May-07-06 9:00 PM EST –

yourself to know it's a "bad idea."

I have also used "Great Stuff" and other liquid foam products and I can tell you two things:

1. This type of foam IS NOT meant to fill high volume spaces. As another mentioned, it will not cure in the center. It's designed to fill wire/pipe holes and cracks.

2. It will expand as it cures and possibly warp a plastic boat.

used it
I’ve used it on a couple occasions, one being an attempt at floatation.

It will not warp a plastic boat but it wont cure right and will take too much of it to make it worthwhile.

Great stuff is great stuff
It is really ideal for sealing leaks in house and building construction, but I too would not use it on a boat.

Float Bags…
I experimented with the stuff to fill some space in repairing dings in my waveski with the EPS foam core. The stuff is definitely porous and spongy once you break the cured smooth surface. It will take on water. I blogged what little I used with a mix of microballoons and epoxy to ensure it doesn’t take water.

Getting float bags will be just about the same in cost (cans of that stuff needed to fill the space you’re thinking) and be much more effective in the long run.