The unmanned boat went in circles for at least a half hour.
Crews let the boat run out of fuel before stopping it.
One of the men on board said he and a friend were trying to catch sharks about two miles from shore when they hit a wake and got thrown off the boat.
He said they swam for their lives to avoid getting hit by the fast-moving boat or bitten by the very sharks they were trying to catch by throwing chum in the water.
A passerby rescued one of them.