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Tim,
I don’t think you will start an argument. Some, myself included will just say that anything that raises the center of gravity reduces all forms of stability. But reducing stability increases the period of roll and that makes for a more comfortable boat.
Dave Gerr's book "The Nature of Boats" is great but in the next paragraph after explaining his rule of thumb he says, to paraphrase because I don’t have my copy handy, "a sparmaker or navel architect will calculate the required moment of inertia based on the boats stability but this rule of thumb will get you into the ballpark for the average boat in average conditions." I think that if you do want to work it out for yourself try “Skene’s Elements of Yacht Design.” It is easer to read and has a very nice simple method that works well for everything except the very modern high tech boats and then you need to look into "Principles of Yacht Design" by Lars Larsson & Rolf Eliasson. But do it your self design has one problem. If you don’t know what you’re doing you can make mistakes without seeing a problem until the rig comes down. I think the best thing is to talk to a spar shop and avoid problems.
All the best,
Robert Gainer
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Study the history of naval architecture and move forward knowing what didn’t work before.
Don’t waste time making the same old mistakes but instead make new ones and to insure your place in history be sure the mistakes are big ones.
Never design a mast that is weaker then the boat
Never design a boat that is weaker then the mast
Never listen to someone describe why your project will not work unless they can show you the broken pieces of their own version.
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