Have no idea if this will help. We were getting water in our '91 M26 everytime it rained. One nite, I crawled in the boat will it was in the driveway (ah, trailer sailers!) and its was pouring rain. Using a flashlight at a very glancing angle to the cabin side, I notice muitlple trickles coming from the joint between the cabin roof/deck and the hull. Funny thing was these trickles were evenly spaced. I figured they were coming in thru the bolts that held the top and hull together and those bolt heads are coverd by the rub rail. So I ran a bead of clear caulk along the top edge of the run rail around the entire boat. Amazingly the boat has been 100% dry since then...16+ years.