I installed a Ronca 10 on my 2016 CW-28. My solution was to install a 1/2” stainless steel bolt side to side, through the tunnel, so that the chain and (when fully retracted) anchor shank run under the bolt. I also put a short section of rubber tubing over the bolt. I positioned the bolt so it holds the shank low enough that the point of the anchor can’t reach the stainless steel plate. It works great and also snugs the anchor so that it doesn’t swing around when fully retracted. The tubing keeps everything quiet and keeps the chain from jumping during deployment and retrieval.
I don’t have photos but can easily get some if you are interested.
Drilling the two holes was most challeging, but I used a small cordless drill with a short speed bore bit and drilled from the outside of the tunnel by reaching down into the anchor compartment. I then drilled the second hole with a longer speedbore bit through the first hole and across the tunnel. NOTE: First I drilled from the hatch side with a long 1/8” bit to get the location for both holes.
I was worried about the strength and thickness of the fiberglass in the tunnel, but it is very robust and worked well.
Feel Free to contact me I you have questions or want photos.
Jerron Walker, Crazy Heart