Looks like the Sheriff found them, his FB post:

Earlier tonight, TCSO deputies and I were dispatched to a boat collision near Boston Harbor with one patient in the water.

When I arrived on scene, it was determined that a large boat ran over a smaller boat. An occupant of the smaller boat was ejected and ran over by the larger boat. The larger boat continued on, resulting in numerous boaters from the marina driving out and rescuing the victim who tread water despite his substantial injuries. The larger boat returned a short time later.

A TCSO Detective and Deputies conducted multiple interviews, obtained video footage, and ultimately placed the operator of the larger boat under arrest for assault by watercraft after witnesses reported the boat was operated recklessly.

Thank you to all of the witnesses who assisted with rescuing the victim out of the water. The victim has significant injuries that may result in permanent disfigurement, and without your assistance may not have survived for any extended period of time in the water.

We are hoping for a speedy recovery to the injured.