RedactedNarrative: Vessel 1 (V1) was traveling southbound, parallel to the shoreline in the Atlantic Ocean.   V1's occupant saw a dive flag off to the starboard side of the vessel.  The occupant verbally alerted the operator and he immediately pulled back the throttle to neutral. Once settled in the water, they realized a snorkeler had been struck by the vessel. 
  
  
  V1 immediately turned around to render aid.  The victim was brought aboard V1 and taken to the shoreline where E.M.S. and Fire Rescue Paramedics were waiting.  Victim was transported to St. Mary's Hospital with critical Injuries. Snorkeler injuries:Amputation right arm, fractures and lacerations to left wrist, left leg, right leg.