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Reply to: Nacra mast rotation

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[quote=BigWhoop]The point of the mast rotation is to control mast bend. Your mast will bend more, much more, sideways to the mast section than it will front to back.  When you set up the mast rotater tight like that you are preventing mast bend and keeping the sail full. Good for light to medium not so good for heavy winds. As a rough rule the rotater wants to point at the side stays, so allowing a touch more than 45 degrees of rotation on each side. As the mast rotates the thinner, bendier section points more forwards, the mainsheet tension pulls backwards, the mast bends and pulls excess fabric out of the middle of the sail. This changes it from full (like a glider, slow speed) to flatter (like a jet, higher speed) airfoil. If you have diamond wires they limit the amount of mast bend you get and so are set according to your weight. Lighter crews have slacker diamond wires to allow more bend to flatten the sail more and control the power. It looks "wrong" to allow more rotation and have the mast point more sideways in the boat. Look at the big picture. The sail is a lot bigger than the mast so the bend is more important than the angle of the mast.

When it is set up right it's like an automatic transmission. When the wind is light you sail with a soft mainsheet and the sail is full to push the boat through the water using all the available power. As the wind gets stronger you sheet harder, the mast rotates more, the mast bends more, the sail flattens, and the required righting force (you on the trapeze) is limited to what you can provide.

Cool, eh?

I can't help you with diamond wire tension on a NACRA but this guy probably can:
http://www.columbussailingclub.org/pdf/nacra_5.2_tuning_guide_by_R._McDonald.pdf[/quote]

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