RedactedNarrative: V1 was parked with the engine off in the middle of Cayuga Lake with a float attached to the rear. Operator of V1 is the only occupant onboard V1. V1 operator starts engine and subsequently backs unsafely toward the float, attached to the rear of V1, which was occupied by the victim. Victim was subsequently struck by the prop of V1 causing injury to her right hand. No damage incurred to V1.