Answer;
-Prevent Propeller Strikes
Step-by-step explanation;
Propeller guards, or prop guards as they are commonly called, are devices that mount on the lower unit of an outboard motor.These propeller guards surround the propeller and protect it from damage when encountering a rock or other underwater obstacle.
They are manufactured from mild steel rod or heavy plastic, the guards allow water to flow freely through them, so the propeller is able to get a good bite on the water. Grass and weeds are also kept clear of the propeller, and damage to propellers, bearings and seals is greatly reduced through the use of guards.