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!

f 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?

A 35s5 is barely faster than a Express 30 and the Express 30 might beat
it around the cans with a good crew. Both are pretty quick boats. The
main difference is that the 35s5 has nicer cruising/family setup than
either the Express or C&C.
I prefer the C&C 34XL to all...accept for the draft issue.

RB
35s5
NY

"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

On 22 Jan 2006, "Bob Crantz" wrote:

How does one calculate time differences per
mile using PHRF?

Even if not one design and if conducted under a PHRF rating system,
not all races are scored on a "per mile" basis. IOW, there can also
be time against time or other variations (including, too, by building
in the handicap "up front" by stipulating which boats will start at
which different pre-agreed times based on their ratings in light of
the length of the course, then just calculating who finishes in what
order whether or not for the purpose of the particular race also
calculating the differences in finishing times).

Other race sponsors might also adjust the competing boats' ratings
over time based on some pre-agreed standard depending who finishes
when in the last # number of races; etc., etc.

Is it some type of square or cubic law?

For a straightforward time/disance conducted race, all that most
commonly is needed is a simple arithmetic calculation -- i.e., just
multiplying the difference in seconds at the finish depending on the
particular boat's rating by the number of miles of the race.
F'r'instance:

If a C&C 99 has a PHRF of 99 [is racing against a B] 35s5
with a PHRF of 132, wouldn't the 35s5 then be almost
indistinguishable from an Express 30 with a PHRF of 139?

In/for this example for a time/distance race, the C&C "owes" the B 33
seconds/mile, "owes" the Express 40 seconds a mile, and the B "owes"
the Express 7 seconds/mile.

Over even a typical 'round-the-cans (i.e., comparatively short)
course, e.g., 5 to 8 miles, on a seconds-per-mile basis these are very
far from "indistinguishable" differences (even if all three different
competing boats were to finish within seconds of one another, as also
is not uncommon).

Bear also in mind that (although in this respect, too, often with
pre-agreed variations) most race participants and race committees will
have agreed in advance that the course for a particular race will be
selected at race time to try to accord more or less equal lengths to
an as near as practicable upwind, downwind, and broad reach leg (or
something close to that) and that these different points of sail can,
in turn, materially affect different boats' over-all performances
depending far more on skill of crew (if the rating assigned has been
well-calculated) than on a particular boat's inherent design.

Of course, (if there are such) generally prevailing weather and
related sailing conditions can (more or less) "favor" some boats as
against others and, if/where so, it is open to the participants and
race committees to address this factor.

E.g., it may be that in some particular location it is quite common
for wind often to diminish beginning early in the evening and yet for
races to be held at that time of day and, if so, this factor may favor
the lighter/faster boats especially over comparatively shorter courses
quite apart from the rating assigned itself (which is one reason why
in such areas there might be some agreed adjustment in the otherwise
assigned PHRF depending on historical performance of particular boats
and crews; or not, as the case may be).

Granted, it is fun to win and the "type-A" personality-pariticpants
might feel a "need" to win; but the basic idea is: have a good/fun
time while more less fairly testing one's skills - not necessarily
(let alone preferably) a, "Yuh gotta be a 'rocket scientist' (or cube
root calculator)!" kind of Thing.

Thanks!