The model I am building now is using an old trailer screw jack (advise!!!! get the grease off first) and I measured it tonight and it takes a little over 30 turns to go from up to down, On my other centerboard boats I always left the board up except to windward. This is just the test to see if it works stage so there will be changes to be sure. The top of the plate I have added the a lower end of a open-ended turnbuckle with the upper end a swivel, The inside of the swivel is tacked (brazed )to the inside screw mechanics of the jack. The whole thing is way to big to use in real life as yet and it will have to come down in size a lot to fit inside the center board trunk. I tried to get a single lever ratchet to work but it was too much like hard work. Plus I ran out of beer that day. The idea was to take the wheel hub of the kids bike which is about 10 inches across and hook it to the ratchet so one turn of the ratchet would be about 15 inches of movement, but like I said that didn't go far as the spokes on the wheel couldn't take the pressure and crumbled under the load. Well the kid gets a new bike for Christmas from a mysterious source. . And any questions about the bike,, well I never saw that bike, what missing wheel??? So I moved on back to the screw idea because I like the thought of some method of a lock down in rough weather. Mike