First, an important reminder on avoidance of costly damage to the watercraft:

One of best ways to avoid damage to the PWC’s are to not start the engine in too shallow of water. The suction on the underside of the watercraft into the jet pump system is very strong. The PWC’s should be in at least 3 - 4 feet of water before starting (mid-thigh to waist level). Likewise, when heading into the shoreline or a dock, the engine should be shut off while in 3 - 4 feet of water and let the slight momentum float you the remaining distance to disembark. The cost to repair/replace the damage to the impeller and wear ring caused by rocks being pulled into the jet pump can be anywhere in the $400 - $600 range to the rental customer. This can also leave the operator stranded if damaged at a distant location from the dock and ruin a great day of fun.

Below are a few images of recent jet pump impeller and wear ring damage. The wear ring is the blue plastic sleeve made of Delrin.