Oh.....wow. Yeah, that sucks.

I'll have to think on that for a bit...my first thought is to try and find a piece of thin firm extruded tubing (polyethylene) that you could cut a groove in and slide it and the bolt rope into the hull. McMaster.com has polyethylene tubing in just about any size and wall thickness you can dream up. A razor blade should open it up to receive the bolt rope and loops. After that, you might consider injecting epoxy into the groove but that could really get tricky...not sure I would try that or not.

I'm just throwing out ideas, but what if you used said poly tubing (sized right to slide the bolt rope), left it whole, plugged the ends, masked of the boat really well, filled the slot with thickened resin, slid in the tubing, let it cure, then cut/route out the tubing to form the opening for the bolt rope.

Can you physically flex the bolt rope slot?

I can't quite make it out in the photo - what kind of profile is in that groove? Is it rounded (i.e. a "C") or wedge shaped like a sideways "V" open at the bottom.