RedactedNarrative: OPERATOR 1 WAS OPERATING VESSEL 1 WHILE CRUISING ON PLANE. AS OPERATOR 1 WAS UNDERWAY WITH VESSEL 1 HEADING TOWARDS THE LOCK AND DAM OF THE WATERWAY, OPERATOR 1 FAILED TO SEE A ROCK UNDER THE WATER LINE DUE TO THE MURKY WATER CONDITIONS. VESSEL 1 IMPACTED THE ROCK IN THE WATER CAUSING DAMAGE TO THE LOWER UNIT PORTION OF THE OUTBOARD MOTOR. THERE WAS NO INJURIES SUSTAINED TO OPERATOR 1.