I just recently purchased an 81' M17. During my first sail I was unable to lower the centerboard. on returning to the dock and trying to fathom the cause I found that I could not push the line more than 1-2 inches into the hole of the centerboard trunk. I then obtained a rubber mallet and whacked the side of the centerboard trunk several times without success. I then squirted some WD-40 in through the hole in the centerboard trunk and gave up for the day. I returned to the boat several days later to find that the line to the centerbaor was moist and could now be inserted into the centerboard trunk for its entire length. The line could then be pulled out its entire length, stopping, appparently by a knot at its most distant end. There was no resistance on pulling back on the line and the line can be re-inserted to its stopper knot outside the centerboard trunk, being soaked and dripping with water. My deduction is : 1. the line detached from the centerboard 2. the center board is down or dropped off and out of the centerboard trunk My thoughts on ascertaining the status of the centerboard include: 1. careening the boat at the dock with the main halyard and probing the keel with a long pole 2.beaching the boat and, again, doing some sort of probing or inspection of the keel. 3.have two people place a line under the boat and, as if keel-hauling,walk the line line aft-to-fore outlining the bottom of the keel and (hopefully) the centerboard. 4.diving the bottom. The boat is berthed at Folsom Lake and the water is quite cold at this time of year with all the snow-melt and fresh run-off. If anyone out there has had any similar experiences and/or ideas please let me know via e-mail at the above address. Thanks, Manuel Stein