RedactedNarrative: Unit 1 had just launched from the landing, and while attempting to power up the boat, the bow rose and the stern dropped and the foot of the motor struck and underwater obstruction.  When Unit 1 struck the unseen, underwater obstruction, Unit 1 leaned to the starboard side, ejecting the two passenger and the driver into the water.  The driver of unit 1, struck his shoulder and chest on the steering area of Unit 1 causing his injuries.