Hi Moose1am-

We have placed stone in the holes several times, including large revetment rip-rap. It is pretty amazing how far some of those large stones get moved. Part of the problem is that rip-rap does not stop erosion. We know that on shoreline work and use a geo-tex fabric underlayment to hold the soil in place; and the rip-rap basically holds the fabric in place. On a ramp, the prop wash is so strong that it goes between the spaces in the rip-rap and blows the mud out from underneath. Then any stone that so large that it can’t be blown away ends up at the bottom of the resulting hole.

Our best success is with something that we will be extending this winter while the lake is down. That consists of refilling the holes with rip-rap, and then grouting the rip-rap in place with concrete. The places we have tried this seems to hold up well and are smooth enough when finished to not cause problems with props or trailers. And it doesn’t really cost much to do when the lake is down anyway.