it has a bypass valve to help minimize damages if you strike something in the water. I don't think it saves the prop so mucgh as keeps the engine from snapping in half. Other than that you just have to push the switch and wait. As long as we are talking about bypass valves ... always use the trailering bar when towing. More than one person has plowed a groove in the pavement because they hit a pothole and triggered the pressure relief valve.