Getting my 84 mac 25 ready for the water and found the jib winches in sad shape. One is completely frozen up the other works poorly. I suspect the winches are original equipment. I loosened the three nuts holding each to the boat but they were still solidly stuck to the boat. There is a very large screw accessible where the crank attaches. How do I remove and dismantle these winches. They are black, but I didn't write down the name of them.. any help out there ?