RedactedNarrative: Vessel 1 was southbound when the driver let go of the steering arm of the tiller steer engine.  Vessel 1 made a hard left turn, ejecting the driver.  The passenger regained control of the vessel and went to help the driver.  Passenger threw the driver a life jacket and held onto the driver because he was unable to pull the driver back in vessel 1.  A short time later a vessel came by and assisted the passenger in getting the driver back in the vessel.  Driver was transported to the hospital due to hypothermia and ingesting water.  Kill switch was attached to the motor but not to the driver.