Carlos wrote: > Question for Jerry (and any others that would like to add thoughts/ideas)-- > > Do you think the idea of improving the cockpit drain on a 1979 M17 in the > manner described below has merit? > > Install a 1 1/2" plastic through hull (vertically) at aft end of cockpit, > just above OEM drain, and install another plastic > 1 1/2" through hull in transom (slightly below first through hull installed) > and connect the two through hulls with reinforced hose. A one way Whale > valve would be installed in middle of hose run. This valve is to stop water > from backing up into cockpit. The transom through hull would be above water > line, thus removing the need for the below water line OEM through hull. I am > considering one through in aft-center of cockpit, as this is the area that > has a low spot for water to be removed and where OEM drain is located. Two > through hulls may be installed (one at each aft corner of cockpit) for twice > the volume of water removal. With this installation, some water would not be > removed, as the low spot is at center of aft cockpit. > Thoughts? I have an '83 M-17, and from your description, it sounds like the cockpit drain arrangement changed. Mine has two holes from the cockpit into the aft locker front corners, when immediately drain into a hose that goes to a below water line aluminum tube that was glassed in. The cockpit drain exit is below waterline.
I have considered what I would do to make this more robust. First off, plastic through-hulls should be well above waterline. Consider the use of bronze through hulls instead, for two reasons. First, they're more robust. You're going to be storing stuff below that may rattle around and bump against the hoses , stressing the plastic piping that the hose attaches to. With bronze, you have peace of mind that the through-hull will never fail. Second, silicon bronze through hulls are extremely corrosion resistant, which is why they are the ONLY suitable below water line through-hull material, for both fresh and salt water. Next topic, the Whale valves. The new production M-17's have them, but it's a short straight run from the rear of the aft locker, to the above-water line opening. If they jam, they are easy to un-jam. A whale valve in the middle of a hose between the cockpit drain and the through-hull is a Murphy's law attractor. It will jam so your cockpit won't drain, or it will break, again because of all that stuff ratttling around below deck. Or the hose clamps are too tight. Simple solutions are better. Uncut single run hoses are better. The whale valve is a optional feature, not a necessity. If it jams, how can it be un-jammed? The ockpit drain system should be very robust. Adding parts creates opportunities for trouble. I keep a cork in the cockpit drain entrance for ordinary times, to keep the aft cockpit locker dry from reverse flow through the drains. If it gets rough, I remove the corks, so that if I'm pooped, the water will drain properly. If you have the OEM below waterline glassed-in aluminum tube, and you're going about the installation of a new cockpit drain, I suggest use the existing hull opening. Cut off the aluminum tube, circularize the hole, and install a bronze through hull. The less hull penetrations, either above or below the waterline, the better. Fair winds, and happy days sailing, John Fleming, M-17: Star Cross'd _______________________________________________ http://mailman.xmission.com/cgi-bin/mailman/listinfo/montgomery_boats
