Rick, there is no fair way. I am the messenger from the area that has both 10 and 15% adjustments. Neither is perfect, and the deviation from perfect depends on the wind.
Our Wednesday racers give a 10% adjustment for no spin. Our venue (you've been here, so you know) is a long, rather narrow river (mile wide, 5 miles long). Much of the wind is from the north or south, so there can be some 2-3 mile spinnaker runs. Only when it is blowing hard (around here, 15 is hard) does a non-spin boat with 10% have a chance. Our Saturday club gives 15% for non spin, 7.5% for asym tacked to the bow. It is better and sometimes is favorable to the non-spin boat. When it is blowing hard enough so a non-spin boat is near hull speed, the advantage of having a spinnaker doesn't really increase the boat speed that much. So, (except planing boats) the 15% which is spread over the whole race gives the non-spin boats a good advantage. We thought about other schemes, but what we have is simple and more fair than a single number (11 seconds) or some other idea. The Charleston Ocean Racing Association) (CORA) has a good method which is based on the percentage of the jib area to the main area, figuring that a boat with a small jib and therefore a smaller spinnaker doesn't get as big an advantage from the chute as one (like my 30) with a large J measurement and thus a large spinnaker. But, you would have to spend a lot of time doing the calculations - our group didn't want to go through the effort (old guys set in their ways, they didn't want Time on Time for the same reason, can't tell if they did OK by the end of the race). Good luck - I've spent a lot of time on this (arguing against the folks who don't want any adjustment) so, if you need any more ammunition, email me offline. Gary Nylander St. Michaels MD gnylan...@atlanticbb.net ----- Original Message ----- From: Rick Brass To: cnc-list@cnc-list.com Sent: Thursday, February 28, 2013 1:41 AM Subject: Stus-List PHRF ratings - Spin vs non-spin I help out with a local charity regatta called Pirates on the Pungo. http://www.piratesonpungo.org We are planning to do a couple of special trophies this year, one of which will go to the C&C sailboat that finishes first in the long pursuit race on the first day of sailing. While we plan to have both spin and non-spin classes for the PHRF boats in the regatta (with sub classes to keep the competition fair for all size boats), we want the special awards to span both spin and non-spin. NCPHRF, unlike some other regional PHRF groups, does not grant different spin and non-spin ratings. And the PHRF base ratings that we use for a lot of the casual sailors presume a spinnaker. So we're thinking about creating an adjusted "NON-SPIN" rating for the boats in the special trophy groups that will let them compete relatively fairly with the spin boats in the same special group. I've been told that one of the clubs in Oriental, NC adds an arbitrary 11 seconds to the NCPHRF spin rating to get a "non-spin" rating - regardless of the size or type of boat. That doesn't sound like it would be fair to the smaller boats like the 24, 25, or 27, and it might be generous for the larger boats like my own 38 or Charlie Nelson's 36XL. During the past couple of weeks there was some discussion of how various clubs and local groups calculate a "non-spin" rating that lets all boats race in one class. I seem to recall one message that indicated 10% or 15% of the normal rating was added for a boat racing non-spin. But I think there were other methods, too. So the question for the wisdom of the list is this: What is a fair way to adjust the normal PHRF rating (which presumes a spinnaker) for a boat that is racing non-spin? Thanks for your input. Rick Brass Washington, NC ------------------------------------------------------------------------------ _______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com
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