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William R. Watt
 
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Default San Juan 21 swing keel problem

Lee Huddleston ) writes:

I found that the cable does, surprisingly, attach to the upper/aft end
of the keel. It goes like this: The end of the cable goes through a
hole in the mast compression post and is pinned with a bolt. The
cable runs aft to a block attached to the keel. It makes a 180 degree
turn and then run forward to a sheeve (sp?) also in the forward side
of the mast compression post. The cable makes another 180 degree turn
around the sheeve and heads aft through a hole in the top of the
centerboard trunk to a winch on the aft end of the trunk. Did that
make sense?


running the cable thorough blocks like that provides mechanical advantage
which reduces the force needed to raise the 500 lb. I think from your
description the force is 1/3 of what you'd need to raise the weight directly.


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