RedactedNarrative: The operator of the vessel was traveling southbound on the hillsborough river.  The boat operator was traveling in a safety vessel for a crew team. The operator struck a submerged piling outside of the designated channel.  This collision caused the tiller to make an abrupt move to the port.  When this occurred, the operator was sent the other direction and overboard.  The engine cut off switch was attached to the operator but slipped off the clothing when she entered the water.  This caused the vessel to continue in a circle around the operator.  When the vessel did this the bow struck the operator in the head.  The vessel continued and the prop caught the clothing of the operator.  This action caused the prop to stop and eventually the vessel.  The operator was injured with a slight concussion and bruise/scrap to her left bicep.