sail area/ displacement ratio

[joeh]

hi all
how would one calculate the above ? say you are 420 sq feet and 4 tons

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[boatless]

'Light ship' displacement in Kgs divided by area of main and 100% foretriangle in square metres will give you a comparison with magazine tests.

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[Roberto]

the formula usually used is

SA/((displ)^(2/3))

where SA is sail area in sq ft
displ is "hull volume" in cubic feet--> displacement in pounds divided into 64 for salt water, this is raised to two third power, which means you square it and then take the cubic root




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[snowleopard]

<A target="_blank" HREF=http://www.sailingusa.info/cal__sad_ratio.htm>Here </A>is a site that explains it all very well and does the calcs for you.

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[ChrisE]

It's a grand site. However, it categorises my Rival 38 as a cruiser/racer! I'm falteered but......

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[Georgio]

when entering the sail area, I assume you are refuring to a full main and 100% jib (not 140% genoa for example)?

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[dickh]

I've just done mine - "High Performance Racer!!" - Jaguar 27! - Ellen Mcarthur here I come!


Just double checked - it's only a 'cruiser racer'.........

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I'd rather be sailing... /forums/images/icons/smile.gif

 

[gjeffery]

My AVS is 198 degrees!

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[joeh]

i understand that the conventional rule says that u shld use 100% foretriangle when using the formula but any headsail aft of the mast is there right ? it is power and should be used in a power to weight ratio . especially so when trying to compare overlapping / non overlapping jibs, masthead/ fractional boats. i used both measures and they produce quite different ratios for a masthead.

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[AlexL]

apparently -(YM or PBO had an article recently) the sail area is the 100% foretriangle i.e 1/2*J*I plus the main triangle with all roach removed ie. 1/2*P*E



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[mirabriani]

Apparently mine is a racer Trapper TS 240
All this time I thought my seamanship was the reason I zap so many others!
Regards Briani


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[dulcibella]

I got a negative value for AVS on a Rustler 36 until I realised I'd put in a daft figure for hull draft. After correction it came out as a credible 154. Garbage In Garbage Out ....

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