Sail loads

[laura]

Right - I know what values i want to assume, for sail area, height, foot, camber, position of max camberetc... the part that is still not jumping out of any booksis how to ROUGHLY work out a crude estimate for the loads in the sail ... can any one PLEASE help. It is now driving me nuts and stopping me from sleeping.

laura

[SailDesign]

"It is now driving me nuts and stopping me from sleeping."

Nothing is worth that aggravation.. ;-)
You may want to talk to a sailmaker - they are the ones with the knowledge in that department, or at least they _should_ be.

Steve

[mmd]

Hie thee off to thy local library and immerse thyself in Marchaj's "Sailing Theory & Practice"; thou wilst find enlightenment therein.

[BrettM]

The back of my harken catalogue has some generic formulas for sheet loadings. If only I could find it... so I would suggest that you get one. I do not know if they are accurate or not though.

Brett

[jonathan]

What I sometimes use is that at 15 knots of wind, the pressure is about 1 lb/sq ft. Varies approximately with the square of wind speed. Now if that's not rough enough !

good luck

[dionysis]

I think what you are looking for is a spreadsheet that calculates the dynamic pressure of the wind, as the windspeed inceases. It would be nice to be able to calculate the lift and drag forces per square foot of sailarea, depending on the sailing direction. Maybe this spreadsheet will help.

cheers.

[SuperPiper]

I have seen the formula and several tables converting air speed to pressure.

I have never been able to find the same information for converting water speed to pressure. There must be some relationship: most outboard boats use a submerged pitot tube to drive an analog speed indicator.

Has anyone seen such a relationship?

[tspeer]

The formulas for converting water speed to pressure are the same as for air. Only the fluid density is different.

[Stephen Ditmore]

There's another approach you can take if you know the boat's maximum righting moment. The total sail pressure will not exceed (except momentarily) the maximum righting moment / the heeling arm.

A comment from you would be welcome at http://boatdesign.net/forums/showthr...4330#post14330, Laura. I'm happy to know it's not only guys awake at night sweating this stuff.

Stephen