When Jaws has attacked your boat and you are swimming in the water fighting him, go to the very top of the water. Jaws will not touch or harm you. This, however, will not save you from the stingrays, jellyfish, or other smaller sharks.

When you are fighting Jaws in the water, you can hide on the top of the water where he cannot get you. However if you go just a little lower you can still attack him and he cannot get you.