If they are made of PVC you could use a waterbed repair kit. You must smear glue on both the patch and buoy and DON'T TOUCH IT for several minutes. Then stick 'em and maybe squish with a stack of books. Don't fiddle with it! One touch and it will peel off. If done right the 2 pieces melt slightly and then stick together as one final item, welded. Small pinholes can be patched with glue alone (rarely works).