Solid flotation does not have to be in one piece. Get some packing peanuts and a mesh bag or several mesh bags. It is school time, so look at K-mart , Wal-Mart, and such large discount stores for mesh laundry bags. They are reasonably cheap and have a large mouth with a drawstring closure. Fill them with as much packing peanuts as you wish. If you are short on the "peanuts" get any old foam packing material and rip it apart into chunks. After a day on the water, remove the foam-filled bags and just let them hang to drip and dry. if youput them in the sun, and give them plenty of circualting air, they'll stay mold free, and be ready touse the next time you go out.

Eventually these things get grungy. dump out the foam, clean it or trash it, and through the bag in your washing machine with a good dose of non chlorine bleach. When they are clean and dry you can restuff them for another few years of use.

hope this helps.

PGJ