need a link to PORTSMOuTH cat numbers

www.ussailing.org/portsmouth/tables2003.htm

The 2004 numbers do not appear to be out yet.

http://www.ussailing.org/portsmouth/tables03/tables03mh.htm

Gang,

Thanks,..got it,......I see NO number for a I-20 without spinnaker,..what does one do now?

regards,

Bruce
St. Croix

Install a spinnaker.....

Use the US Sailing Modification Factors. -- Boats rated w/ a spinnaker that don't have one. I think it is factor SN, which means mulitply the rating by 1.020.

http://www.ussailing.org/portsmouth/tables03/modifications03.htm

Bruce,
Go to this link at US Sailing and look at Code SN.
http://www.ussailing.org/portsmouth/tables03/modifications03.htm
Dave

Ha

It so happens that there was not enough spin boats for a class,....so the I-20 kindly agreed to sail non spi,...

We orinally planned to use Texel,...which has a calculation avaiable,...spin and non-spin for all boats,..posted or not..

..so to keep peace amoung warring islands,..force was yeilded to Portsmouth,....so,...instead of being the 'magic bullet' to cure all ills,....it created a new one..

..ok,..if there is NO posted Portsmouth number,..then you are SOL,.....for , as I understand,..one cannot just 'make-up' a Portsmouth number.....

comments.?...suggestions..

Bruce
St. Croix

ps; regatta is Sat-Sun-Monday,...come on down!

Bruce,
Someone will correct me if I am wrong, but this is how I'd calculate this situation.

Take the I-20 at it's Portsmouth numbers in the various Beafort wind ranges and multiply that number by the SN modification factor for that same Beaufort wind range.

I come up with 60.38, 64.68, 61.71, 59.77 and 57.67.

This may be entirely wrong, but that is how I see the picture.

Hope this helps.

Dave

Dave,
Thanks,..that looks like a winner.
We will be in Beau 4 day 1, building winds Day2, Day 3 most likely in B 5

..all in all,..15-20 mph,...2 foot rollers,...air temp 85 f,...water 72 f-ish....will put results up for you Northern types to enjoy.

thanks again to all,

regards,
Bruce
St.Croix

Brobu walk up to that US I-20 of that guy wanting to participate and measure his mainsail area. Carry a bathroom scale and measure ready to sail weight as well.

Than Texel or ISAF will produce a number.

PN can't just statistically produce a rating number out of thin air.

Wouter

I guess I'm missing the point here.

You're sailing portsmouth, hence needing a #.

You use the correction of a spin boat, not flying one.

There's no # for with and without as you say. You have to use the correction, as has been said.

I guess I missed the point somewhere

I agree with Todd. This isn't rocket science. What's so hard to figure out? US Sailing has a Portsmouth Rating for just about any catamaran you're going to run into. There is a rating for that boat. Use the modification factors to alter the rating. If you want to know what an Aqua Cat rates with a Hooter, double traps and a skipper and crew that weigh 500 lbs. you can come up with a rating using the modification factors. When all else fails, read the directions.

Hello All,

..yes, I agree with you all,...it is not rocket science...

...the Texel site even has a spredsheet(Excel) download with the formula in place,..you just put in the numbers,...and let a calculator do the rest

...in this case,,, just change the mainsail size to that os a I-20 North American stock sail ( from the factory),......

...that is why the formula( based on on finite measurements) rating systems are nice,....a 327c.i. 300hp chevy engine is the same every year,....not 350 hp one year,...and then 295hp the next year,....a crude analogy, but the point is clear

..keep is simple,...lets go sailing..

...once again,..thanks to all.

regards,

Bruce
St. Croix

Hi there Bruce,
Am I correct in my recollection that you were doing the numbers on the P19MX a while back? Now it is the I-20. Are both of these configurations giving you a hard time?

Couldn't resist. I've exchanged posts with you before and "am stepping out on the limb a bit". Hope you take it as a little humor, certainly nothing else intended. 🙂

Dave
P19MX "soon to be Tornado spinnaker and snuffer equipped"

Dave,

@@##%%&&***##@

I give up with this quest.

We held the regatta,....the questionable ratings' were not changed.....didn't matter,....a H-16 from Puerto Rico beat them all weekend long

...a good sailor always 'beats' the rating,...yes?

regards,

Bruce
St. Croix

Next time deduct 2 points from the EU I-20 and have a good approximation of the performance. I assumed 1.4 sq. mtr. larger main and 5 7 kgs lighter.

Wouter

The problem you are having with the I20 will fix it self. The US/EU I20 will soon be the same boat world wide known as the Nacra 20. Look for an updated Yrxel number this summer.

With this main, the N-20 in Europe will be the identical specs as the NA boats are. Are we gearing up for a NACRA 20 worlds? Note the specs. At PC site are the old main sail area & not the North America spec. which has become the accepted NACRA 20 one-design