Author Options:

How could I secure multiple 2-liter bottles for use as emergency flotation for a homemade skin-on-frame kayak? Answered

     I'm working on a Yostwerks-design skin-on-frame kayak, and have seen pictures of inflatable bags that fit in bow and stern for emergency flotation - in case you're swamped, they'll help keep your water-filled boat on the surface.
     Part of this project is the joy of spending time making something that I will enjoy.
     Part of this project is about not spending a lot of money - I could go out and buy a kayak, but would need several hundred dollars all at once to do so.  I can afford to buy individual components: a sheet of plywood, or a plank, or fabric, so can work little by little on building my own.
     The specialized flotation bags, while nice, would be an added expense - I'm assuming on the spendy side.  But I drink cheap diet soda, and believe I could reuse the bottles as cheap (essentially free to me, since this would otherwise be trash) flotation.  It would take lots of these to float a kayak plus any camping gear I might put in it - about 25, I've figured out.
     What I can't figure out, though, is how to have 25 empty bottles split between the bow and stern, filling the awkward pointy kayak spaces, and not rolling all around or falling out if I capsize.
     So what do you think?  How would you go about this?  Please let me know what you think.  Thanks!



Best Answer 8 years ago

I'd avoid spray foam, eventually gets waterlogged.  Tough to remove, traps water that is tough to dry out, which speeds up the decay of your kayak.

I agree with RedneckEngineer, use a net bag clipped to the frame.  If construction is not finished, add attachment points on the frame for future ease.

Being able to remove the floats is important, to replace one, and dry the interior.

Couple related thoughts:

1. Kayak float bags are not that expensive, less than $100 for a typical pair. The skin of your craft probably cost that much.

2. You won't need much safety flotation
.  Even a vinyl + aluminum skin-on-frame kayak will be fairly light.  Big Klepper kayaks are about 80lbs, ~1.25 cubic feet of fresh water displacement.

3. When you pack camping gear, most will go into dry bags that can float
.  You don't squeeze all the air out. If you capsize and the bag gets free, it will float (not just be waterproof.)  Thus each attached dry bag is additional flotation.  Check out John Dowd's Sea Kayaking: A Manual for Long-Distance Touring.  One of the kayaking classics, the section on packing will give you a good background.

4. I knew two guys that used kayak cockpit socks (Sea Socks) and liked them a lot.  A sea sock basically is a bag that you sit in, attached to the coaming.  If you capsize, only the sock fills up, the kayak interior stays dry.  This solves most of the buoyancy problem, but note that air will eventually leak, so safety floats are still important.

Stuff always needs to be waterproofed + floating + attached, discovered the first time my car keys sank 10' down into muck...

If you are looking for aditional floating device for kayak, for me sounds good choise of trashbin sacks( they are incredible cheap, high volume, airtight).
 My construction of inflatable ball from sack is this:
1) cut away head of PET bottle (aprox 10cm long)
2) insert head into sack(size 35-60-120litres)
3) with wire , thin rope or ducktape roll tightly open side of sack to strong part of PET bottle
4) overcuting of sack can be rolled back and again tight with ducktape secure airtight attachment of sack to PET.
Now you have big inflatable thing you can insert into your kayak to ensure it will float after crash.

5) safety: it is easy to make two or three this improvised floating bags
Enjoy this solution in your way.

Thanks everyone for the great ideas!  I appreciate your thoughts and help!

@CrLz:  THE WINNER!!  I'll build this in, and use your idea + RedneckEngineer's.  Eventually, I'll look into real float bags.  But for now, that's $100 less and gets me out onto the water faster.  I'm doing this bit by bit as I can afford, and that much $ at once is a big chunk for me.  I know the skin may cost, but am looking into inexpensive possibilities for this, too.  Otherwise, many thanks for all the tips and ideas, especially #3 - hadn't occurred to me, and the book recommendation will one day find it's way into my library.

@RedneckEngineer:  Nice!  I even have one of these, so cost = free = great!

@paganwonder: Simple elegance!  Yep, yep, yep!  My kind of idea - thanks.

@ everyone else:  Thank you very much for speaking up and making me think.  I didn't realize there were so many ways to look at solving this problem!

Peace and lake water,

How about useing a net.  A net laundry bag comes to mind.  I have seen these bags stretch and hold quite a bit of stuff, and they normaly come with a pull string to tie them off.  Which could then also be used to secure to the inside of the boat.  Also if you ever needed the bottles or the netting for other purpose it should be easy to untie and use.

You could seal them in a bulkhead, and as Karletto suggests, secure with expanding foam so they don't rattle.


I would go with heavy duty garbage bags-  the bottles could still be used for other things in an adventure (please note that some people might call these adventures emergencies!)  and there are no end off useful things to be made from a large piece of plastic.    

Adventure become emergency when we panic instead of think our way thru obstacles.  

i would use expanding foam but don't exaggarate with it otherwise you'll have bow bulb :)

i mean
fill the compartment with bottles and than spray the foam between bottles. it's light, it can glue and doesn't brake after xy years. perfect


8 years ago

Pantyhose. Seriously, get a couple of pair of X-Large pantyhose, stuff 'em full of the empty bottles and tie the waistband shut.

Well heck, even a sturdy garbage bag will do that!