"Bob Crantz" wrote in message
ink.net...
How does one calculate time differences per mile using PHRF?

If a C&C 99 has a PHRF of 99 and is only slightly faster than a 35s5 with
a PHRF of 132, wouldn't the 35s5 then be almost indistinguishable from an
Express 30 with a PHRF of 139?

Is it some type of square or cubic law?

Thanks!

Amen!

Doesn't necessarily have to be time on distance, could be time on time. In
any event, in a race "measured" at 6 miles, a 35s5 would have to finish 42
seconds before a Express 30 to correct to 1st. Believe me, having done
enough Wednesday night "beer can" races of this disatance, I can assure you
that 42 seconds is not a lot of time. The 33 sec/mile difference between the
99 and Bendytoe is quite a lot, in most venues these boats wouldn't be
racing in the same class together, the only time they might race
head-to-head would be in a fairly small fleet. In big regattas these boats
might have a whole class between them, the 99 maybe in phrf B, the Bendy in
phrf D.

http://www.westshoresailclub.org/race/Summer04.html

Good example of the class groupings in our local races. In at least one of
the series we (J33) end up racing against a boat rated at 132, the Olson
911.

John Cairns