If you stand on the second floor of your raft and stand right at the edge of the floor making you drop slightly, you can use your empty can to fill with salt water making you not have to go to the main floor.
If you stand on the edge of your platform in the water you will begin a swimming motion. This results in the luring of the shark so you can easily attack and kill and you just back step and stab as it swims under your raft.
