There is a huge rubber ball, into which a human going inside and can be on water while being inside.
But it is very hard to move yourself inside of an ball, you always falling down, and on water you won't move far.
It is possible to make similar thing, but in a shape of an pipe. It will be a rubber pipe. You will be able to move yourself inside of this rubber pipe by walking forward. You will be able to lie down and to sleep inside of this thing.