We had bought the kids one of those swimming pools that you inflate the top ring and then fill the pool up. They come with a patch kit, and the adhesive works under water. When the pool sprung a leak, you could patch it from both the inside and the outside with that stuff-while it still had water in it. Good stuff-whatever it was. I used it for a lot of different things. If you could get that stuff it'd work pretty good I bet.
