If link moves along the screen where rafting flags are and he is swimming. He'll switch to the raft.
Also, When he doesn't have the raft and has no walls on. Tile 0 Appears undeneath him for a split second. And if your quick and turn no walls off, he'll start rafting even if he doesn't have the raft! Displaying tile 0 of course.
Normal rafting works find though...
I take it back, it has bugs of it's own. 🙄