Sorry for the deluge of questions lately... - just trying to finally sort the boat out (after two seasons...) ; and this is the place for really good info.!

I've measured my mainsail w/ battens removed. It's :

Luff - 8105mm
Foot- 2113.3mm
Leech (measured all way round head to clue) 8356.6mm

What is the formula to calculate (...checked USSAiling site but can't open the html. file...) area in sq. mtrs. ?( I actually tried what I thought would do this calculation but came way short of 15sq.mtrs. on a main w/ over 250hrs. this is odd...)...

Thank You !!


Paul

Paul,

Look on the ISAF web site it will be there some where.

It's not that complex IIRC.

http://www.schrs.com/

in specific : http://www.schrs.com/schrsmeasurement.asp?id=main

Best is too devide trapezium S1 into 2 triangles. This is more accurate.

Also for F16 rules you only need to include the mast area that is next to the mainsail. So you can deduct the area of the mast that is below the foot of the sail. (or below the gooseneck)

Also the area of the boom is NOT included in the F16 mainsail area.

Paul, do you currently have a Taipan 4.9 mainsail or a F16 mainsail ?

The Taipan 4.9 mainsails are a little smaller than the F16 mainsails so you should indeed be a little below 15 sq. mtr. If you are way below that number then you probably forgot to include the mast area = about 1.4 sq. mtr. on teh Taipans (10 %)


Wouter

Thank you guy's !!!

PK

Paul: If you are inclined to, I suggest you enter your measurements into Sailcut (http://sailcut.sourceforge.net/)
You will need the head length in addition as well as an opinion for leech round etc, but you will get an accurate surface calculation based on the foil shape. The link Wouter gave will probably give a somewhat different sum (but that's how they will measure the sail at regattas, so that is whats correct!). Playing around with how you think your sail looks in some saildesign software might be a real eye-opener with regards to shape and trim. Setting out to do a design for yourself, and comparing it to flying shapes you see on other boats will definatly be a learning experience (no need to build it). At least it opened my eyes for sail shapes and trim. Before I looked at sails and trim, but I did not really see what it was like. Now, after working some with Sailcut, I know more about what to look for and have a whole different 'eye' for sailshapes.

I entered your numbers into sailcut, and did some guesstimation on head-length and leech round. Came up with 12.93m2, but this is a number with seriously large margins for error as I did a fair amount of guessing without even trying to compare the outline to sails found in pictures etc!

Thank You Rolf !

12.9 sq.meters is the CAD program total for my measurements !? Oh well , how much difference could being 0.8 sq. meters SHORT of the class legal 13.7 sq. meters really make !!!?

Paul

Paul, the number I gave have large (very large) margins for error, both ways!

The largest difference between your current sail, and a "fathead" is that you will power up earlier. But Gary can hopefully tell you more about it, as he recently got one from Ashby (correct, Gary?). A practical report on the virtues of your new mainsail would be good reading, Gary.

Paul, Your sail is a stock Goodall 4.9 sail; I have a tough time thinking that Goodall--co-inventor of the taipan--makes sails smaller than the 4.9 class size.

Paul,

I will let you in on a secret.

A standard Taipan sail was NEVER 13.7 sq. mtr. even if some webpage claimed it was.

A standard Taipan 4.9 mainsail including the mast section is typically 14.54 sq. mtr. So roughly 14.5 sq. mtr. Subtract about 1.4 sq. mtr. for the mast section and you'll end up at 14.54-1.4 = 13.14 sq. mtr. pretty close to your 12.9 sq. mtr. I say !

Also the area for a standard Taipan mainsail was never ruled upon in the standard Taipan 4.9 class rules. They only limit the luff, leech, foot lengths and the width of the sail in 4 places. So there can be some variation in the overall area between compliant Taipan main sails.

For F16 is is just maximum 15.00 sq. mtr. including the mast section and as far as the F16 class rule is concerned your leech may have the outline of a teddybear if you think that will make you faster. Those additional 0.4 to 0.5 sq. mtr. area will all go into the larger squaretop.

Wouter

Doc,

I'm sure Goodall has the sail cut to precisely 13.7sq.mtrs..
My frustration stems from an inability to verify this w/ ANY of three sail area calculations AND , I keep comming up w/ about 12.75 - 13.00 sq.mtrs. as did Ralph...

Hobie 14 Turbo...? O.K. , sending my order off for one of Darryl's A-O's today ( ...i will not be beaten in two classes!)...

Pk

... you'd think by now i'd know to read Wouter's post before reply...

Whew, guess i'll keep the calculator after all...!

Paul

whoops, missed Wouter's post before reply to doc.

Hmmm. guess i'll keep the calculator after all...

PK

damn echo.

PK

Paul,
I just picked up the H14 this weekend. I'm hoping we can send the kids out on it while we do our thing. Its in pretty good shape overall. And you know it's the ticket for those 30 knot days in Santa Cruz. (It doesn't have that goofy comp tip, so I'm sure the Hobie guys will still shun me.)

You might be able to see it at

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1,1&item=4586643087&sspagename=STRK%3AMEWN%3AIT

Paul-
As I remember the Taipan class rules specifically address how to measure sail area with an example? I would think this would give you the number Gregg would provide or is cutting sails to.
Might come up with a slightly different number than the other techniques.

Kirt

Hi all,

Rolf, I would be happy to give a full report on the "virtues" of a "Fathead" main, but I am still searching for some of them.

But seriously, looking at new Ashby fathead 800mm wide at top batten v's old main still wider at top than Taipan main.
The extra head area has basicaly been made possible by cutting clew higher, the area is about the same. So the centre of effort is unquestionably higher in the Fathead, this means it has greater leverage tipping boat earlier, meaning I can get on trap about 2 kts. earlier. This extra tipping moment is easily controlled by using downhaul, which twists the head depowering it.

The sail looks fantastic twisting and flattening as you would like. But it is not the cure all for boatspeed you may be looking for. It is faster by allowing you to trap 2 kts. earlier, but other than that I have been unable so far to find any other advantages, but I am still searching.

I live in hope that it will offer me more than trapping 2 kts. earlier(practical virtue) and being the hottest looking main on a F16 (not a practical virtue, but pleasing to the eye).

Stay Tuned.

Regards Gary.

Doc - congrat's to your boy's on the new Hobie and their instant access to the 20 or so regatta's to which i've no invitation (whaaa !).

My dream is that Hobie will produce their Acat and that it'll be revolutionary and the boat to beat in the international fleet and that it'll fit above my F16 on my trailer and my wife will beg me to buy one so that she can part forever with the eurodite ,champagne sipping, Pirsig reading crowd of friends she has now in favor of the "Hobie Lifestyle" with it's provincial, folksy, promise of campouts , hotdogs , warm beer and trophies back to eleventh place... Yeah , that'd be really great...

Paul,

You know that even if Hobie Europe comes up with an A-cat they can not bring it to the US as Hobies could not possible sail with any other brand without violating the prime dirrective.

M

Mini ,

So the Hobie Acat will be a product of Hobie Europe and ineligible for U.S. Hobie regatta's ? Is the Bush Cabinet advising Hobie Corp. on marketing strategies ? They've killed the dream ; it's Nabakov and pate'
forever...

PK

Naw,

If that was the case everything but the 20 and the 16 would inelligble as everything else is built in France. You have to figure though that a Hobie A cat would be chastised for leaving the fold to race in A-cat regattas, and they sure would not bend to allow other A-cats into the Hobie society.

Matt