RedactedNarrative: I responded to the area of St Augustine Inlet in-reference to a possible jet ski accident. While en route to the scene I was informed by SJSO Air unit that one subject was in the water being recovered by a second ski operator. 
  
  Once on scene my investigation revealed the operator of V1 was in State waters Northeast of the St Augustine Inlet, Atlantic Ocean, jumping waves in the shoaling area which, is inherently dangerous. The operator of V1 proceeded to jump a wave on his stand up jet ski when he turned hard to the port causing his cowling to break off of the ski, causing him to fall off into the water and the ski flipping upside down. 
  
  The operator of Vi attempted to get a line on the ski to tow it to shore however was unsuccessful before Vi sank. A canvas of the area by Air unit and Sheriffs Office vessel's received negative results in locating I informed the operator/owner he was still responsible for the recovery of V1 which would turn into a derelict vessel if not located and recovered. After speaking with the operator of V1. I determined him to be in violation of Navigation Rule 2 "Responsibility" knowingly jumping waves in hazardous waters of shoaling, is inherently dangerous. Rule 6 "Safe Speed" operating outside of safe speed maneuvers to keep him and his vessel in a safe condition. At this time V1 is considered a total loss and missing at sea. USCG sector Jacksonville was notified and briefed on potential pollution issue and environmental danger to sea life.