You're going to need a bigger boat.
Fishermen off Frenchman Island in New Zealand recently encountered a Great White Shark. It repeatedly bit the motor on their boat.
That was pretty smart for the shark, don't you think? First disable your prey's ability to escape, then go in for the kill.
The fishermen don't appear to be concerned. They call out, "Oi! Oi!" as though they're offended, rather than frightened.