# Calculating new CE

Discussion in 'Sailboats' started by paxfish, Mar 7, 2016.

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### paxfishJunior Member

Guys - I'm running a new main this year. One of my goals was to move my CE forward a bit.

My sail plan shows the old CE - how can I calculate the new CE for the main? Ignoring the roach would not be practical for this type of sail, methinks.

Old:

new:

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### DCockeySenior Member

Simplest way (without access to CAD software which will calculate the center of the area) is probably to cut out a piece of cardboard which is a scale version of the area (trace directly from your plan) and find the point where the piece of cardboard balances. That will be the center of area, which for sails is commonly called the "Center of Effort".

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### TANSLSenior Member

I hope that helps.

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### PARYacht Designer/Builder

Simply geometry really, just divide the shape into triangles, trapezoids, rectangles, etc., calculating the center for each, then some deduction and poof a new CE. I'd make the first triangle from the clew to the head, with the foot as the base, so half the height times the foot (perpendicular). Next, I'd divide the roach up into a couple of triangles, same math then calculate their participation in the total area. This could all be done at the kitchen table with a scale drawing and ruler and a calculator (or real old school - a pad and pencil).

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