Hi Alan, I've only got a little M 12, but have worked on a lot of boats. One thing to remember is that fiberglass layup requires gelcoat to be waterproof. Wherever there is not gelcoat, or paint, water can slowly weep through. One of our boats kept getting water down into the keel area and I was baffled. I finally crawled in, opened every cavity, and had my wife blast it with a hose. Nothing evident, and it nearly drove me crazy. Finally, in a big rainstorm I crawled in, battened down and watched. After time, I noticed water barely weeping through the laminate at the hull to deck joint, then tiny drips running down into the keel cavity. I'm not sure of the keel to deck joint in the larger M boats, but in multiple boats I've worked on its an issue. The solution was to pull off the rub rail, drill out the rivets, clean the joint, shoot in 3M 5200, and while it is still soft, tighten new stainless fasteners almost all the way. Then, after the cure to cinch them down another turn. Then, heat the rubrail in a bucket of hot water and re-install. This is all to say that sometimes the sources of the water can be baffling. Go at it methodically and you will find it. Be very suspicious of any area without gel coat, and any joint, which will likely have failed due to age. Also, at this age nearly every cleat and running light and winch will be leaking, too. 5200 is a wonderful product, and should be considered permanent. If you use it, the rep from the company told us to store the unused portion in the freezer and it will store well for the next use. Not knowing your level of experience, I will assume little. If you do anything to the 'glass work, assume it was waxed and de-wax it properly with the right products before trying to add anything--or it won't stick for beans. Do not sand first, as you will just put the wax in the resin into the substrate. Dewax, sand, dewax, wipe down with acetone (wearing Nitrile gloves), leave a rough surface, then add your new stuff--- epoxy adheres well compared to fiberglass resin. Study this matter well on the 'net from good sources, as the toxicity is no joke. My son is a fireman.... Keep an extinguisher... several...handy at all times. Don't breathe the smoke from any synthetic. Two inhalations of that smoke will knock a man flat. Burt Lowry Surry, Maine On Sun, Jun 18, 2017 at 2:47 PM, Alan Oltman <heybuddy@frontiernet.net> wrote:
Hello everyone. I recently bought an M17 and am in the process of repairing and repainting. I have come across something curious I need help with. There is a small fin keel that extends from the keel aft along the center line, to the transom. It is only 5 or 6 inches deep at this aftermost point. Mine looked a little beat up so I thought I’d have a closer look. I drilled a 1” hole in the side, near the transom, and to my surprise, the fin is hollow. Mine, however, contained mud and water. I vacuumed out as much as I could but need to know how mud could have gotten into this “keelette”. The hollow space goes all the way to the keel itself. I can’t see under the cabin sole to know whether the hollow space connects with the cabin. Can I flush it out with water (it was already wet so what the heck)? How can I keep this from happening once I repair this fin? Thanks in advance, AL in MPLS