Keelboat news and development: What is IRC?

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What is IRC?

Printed From: Yachts and Yachting Online
Category: Keelboat classes
Forum Name: Keelboat news and development
Forum Discription: All the latest developments for yachts
URL: http://www.yachtsandyachting.com/forum/forum_posts.asp?TID=2612
Printed Date: 13 May 25 at 3:33pm
Software Version: Web Wiz Forums 9.665y - http://www.webwizforums.com

Topic: What is IRC?

Posted By: chic
Subject: What is IRC?
Date Posted: 17 Jan 07 at 6:06pm

Being a dinghy sailor I'm a novice to the intricacies of the IRC rating system. Although I understand the concept many posts here already assume a working knowledge of it.

Any enlightenment would be a step in the right direction.

Thanks!

Replies:

Posted By: Stefan Lloyd
Date Posted: 17 Jan 07 at 6:46pm

Plenty to read on http://www.rorcrating.com/ - http://www.rorcrating.com/

Do you have a more specific question about it?

Posted By: chic
Date Posted: 17 Jan 07 at 6:58pm

I'm sure I will have after I've read more on the RORC website...

Thanks

Posted By: TimC
Date Posted: 18 Jan 07 at 12:10pm

I'm in a pretty similar position to you chic as I only started yachts a few years ago having raced dinghies for ages.

It seems a pretty good system though and I'm getting my head around it now. The whole optimisation thing is a bit beyond me at the moment though!

-------------
J92s GBR 9224R "Upstart"
twitter.com/upstart_racing

Posted By: chic
Date Posted: 19 Jan 07 at 9:11am

The RORC faq section answers about everything apart from the interesting question about how it is calculated...

Having worked for a sailmaker I understand the sail measurements but I'm curious to know what the critical hull measurements are. Some are obvious but some not.

If anyone can enlighten me with them I'd be grateful.

Posted By: Stefan Lloyd
Date Posted: 19 Jan 07 at 10:59am

If you read the IRC handbook the hull measurements are shown. The "hull factor" is specified by RORC rather than measured. The actual formula is, of course, secret.

Optimisation is a black art. IRC is certainly susceptible to optimisation and does not claim to rate all boats "equitably", unlike IMS which made the claim but failed to live up to it. There is a lot of discussion on this topic on Sailing Anarchy, should you care to search for it. Don't believe half of what you read there! However John Corby and Mark Mills turn up from time to time and clearly know what they are talking about, as does "Jen" who works in the rating office.