The incident took place around 2:40 p.m., Tuesday, Aug. 20, when the man, identified as Stefan Palm, a visitor from Germany, entered the water to take a turn on a water tube and failed to realize that the boat had been left in gear, said the Southhold Police Department.
The action caused the boat to keep moving and the propeller hit Palm in the leg, causing extensive damage to his lower extremities, police said.
One of the people on the boat happened to be a doctor and helped stem the bleeding until Southold Town Police personnel, along with the assistance of Southampton Town Police personnel, were able to provide aid, the police department said.
Palm was transported to Strong's Marina, where Mattituck Fire Department EMS personnel had staged.
He was then transferred to Mattituck High School; where he was airlifted to SUNY Stony Brook Hospital by the Suffolk County Police Department helicopter.
Click here to follow Daily Voice Brentwood and receive free news updates.