There isn't any way to "deal" with sharks. If you're in water that sharks inhabit and they are of the sort to take a bite out of people, you're fair game.

I've never seen or heard of any shark repellents that actually worked.

Best thing to do is stay in the boat.

The number of people who traverse "shark infested waters" without being eaten are huge, the number of people who are eaten or even attacked by sharks is infinitesimal.

Take comfort in statistics.

John E