Hello all, just in case someone with a m25 needs this info, the keel lifting bolt that attaches the lifting cable to the keel is a 3/8" x 3 1/2" (stainless & shouldered,with fender washers & a nicropress nut ).I got this information from Todd,via an email at Blue Water Yachts.
We were able to motor the boat over to clearer water at one of the villages South of us where the water was calmer & clearer, where a diver, no tanks, was able to go down & attach the new cable that I already had made up & fished up through the keel cable guide tube, up to the lifting winch, so we are good to go ! Thanks to all !