: Pool shops sell vinyl waterbags for weighing down the edges of
: winter pool covers. They come in 8' and 10' lengths. The type
: with the bag divided into two compartments is probaly unsuitable
: but the single compartment type should be ideal. You can cut it
: into shorter lengths, toss the valve which is designed for
: water, that gives you good quality PVC with more than half the
: seams done for you. The PVC cement they also sell for repairing
: PVC pool liners works well on this material, just clamp it for
: 24 hours. I have repaired dozens, never had a repair fail. Not
: sure how you handle the inflation valve though . . .

maybe glue in an old valve off a floating pool mat. most of them leak after the first year