What is "oil based gasoline"? Is that what we would call gasoline in the USA, or diesel fuel? If it is diesel, then it should float by itself. I don't know if gasoline floats in salt water. You may wish to check this prior to your event.

Anyway, here is another idea. If you have time, and the sea state permits, what about tying together the floating water container (with some water removed) and the floating fuel container with the cord. If the army survival kit floats, add it to your improvised raft. Put on your life jacket and push your supplies the one mile to your island. You will have to be a strong swimmer, but you might get the most equipment ashore this way. <img src="/images/graemlins/cool.gif" alt="" />