RedactedNarrative: Operator stated he was operating the flyboard conducting what he called “Dolphin Dives”.  The Operator described a dolphin dive as a maneuver with the flyboard where he enters the water headfirst  from the air, dives under water, then comes back up into the air and repeats this several times, similar to how a dolphin will dive and resurface.  During this maneuver, the Operator’s hands struck the bottom of Lake Minocqua causing the remote throttle to be depressed.  This increased the power of the flyboard and further pushed the Operator and the remote control into the bottom of the lake.  Operator stated he was unable to press the remote kill switch because his hand got caught, wrapped around the remote.  To rescue himself, he allowed his legs to go loose, which normally would be kept straight and stiff, causing the force of the flyboard to break one bone in the back of each ankle.  This allowed the Operator to regain control over the remote, activate the kill switch, and float to the surface.  The Operator estimated that he was in 7 feet of water.