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  #1  
Old 10-01-2003
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PHRF Interpretation

Recently, while looking for information on an obscure boat I was interested in, I ran across its PHRF rating. Are PHRF ratings born out of live tests of specific boats and rigs, or are they, more likely, a theoretical handicapping system using dimensional specs?

And, is it possible to use the PHRF rating to make a general, ballpark comparison of seahandling and comfort as well as speed?

Finally, exactly how, or by what equation, are PHRFs determined and why?

Thanks in advance,
Chas
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PHRF Interpretation

PHRF is, as you said, a theoretical handicapping system using dimensional specs.

The PHRF says nothing about seahandling and comfort (and little about speed)

As for "the rule"...
http://www.phrfsocal.org/INDEXED%202002%20RULES%20and%20BYLAWS.doc

Only the first 17 pages are the rule''s general description


more info on cheating the rules:
http://old.cruisingworld.com/powlphrf.htm

and the list goes on. "The Rule" is one of the most wierd systems in existance, and is constantly being changed and developed to more acuratley reflect how to handicap boats. Of course, as it is refined, boats are refined to beat the rule, which is why so many boats have bad sailing characteristics. They''re designed to beet rules, not to sail well. When I can, I try to avoid "rule beeter" boats. (those that are built to have a handicap slower than they actualy are)

-- James
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PHRF Interpretation

Its kind of complicated and not as exacting as one would expect. Its also based on regional results so a boat on San Francisco bay would probably have a slightly different PHRF rating from one on the East Coast.

One thing I do know, if you sail an OK boat, but there is a huge fleet of owners that are terrible sailors, then there is a good chance you''ll get a very favorable rating since some of the handicapping is done by determining averages of speeds and time to travel "x" miles on a course. If you sailed a WizBangSail 34 and everyone that entered races and took an average of 200 seconds to go a mile and you could do it typically in 150, then you are doing good!

From the NE PHRF Site.

"How are handicaps determined? There are a number of factors taken into account. We compare the new boat to others that we are familiar with. We look for boats of the same type, based on sail area to displacement ratios. You really can''t compare an ultralight to an around the world cruiser. We then make adjustments based on the differences.

We look to see if the boat has raced in another PHRF group. If so, the Chief Handicapper of that group will be contacted to get his opinion.

We look to measurement rules. Here you have to be careful as measurement rules are type forming. If the boat wasn''t designed to the rule, then this has to be taken into account. Since measurement rules evolve over the years, the age in the rule must also be considered.

There are a number of formulae that can be used to give you an idea of where to start from using basic boat parameters. These tend to be crude and are good only for getting a ballpark idea of what the handicap might be.

All of these factors are considered and a handicap is determined. It can then be adjusted, based on race performance. This is the difficult part as the quality of the racing program has to be taken into consideration. Just because a boat finishes last all the time or, on the other hand, wins many races, does not necessarily mean that the handicap is wrong.

The overall philosophy is that, for new boats, we should error on the side of being a bit harsh. For instance, if we are trying to decide between a handicap of 111 or 108 for a new boat, we will always pick the 108 for a starting place. It is always easier to raise a handicap than to lower one. "
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Old 10-01-2003
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PHRF Interpretation

...so then what is the exact meaning of the numbers? In your example, 108 is preferred over 111. What is the difference between, say a 178 from a 128? What exactly do the number(s) refer to?
Thanks,
Mark L.
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Old 10-01-2003
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PHRF Interpretation

In theory the numbers represent the seconds per mile that your boat is slower than a 12 meter (rating 0)sailing on an olymipic triangle course. In theory a boat that rates 90 is 30 seconds a mile faster than a boat that rates 120.

The actual ratings are not derived from measurements but from regional comparative performance results of the fleet of similar boats relative other known boats. In other words, if you buy a production boat, that has been raced under PHRF, it originally had a rating assigned and over time that rating may have been adjusted to reflect how well that class of boat has done relative to its rating.

There is no useful information about seaworthiness in a PHRF rating certificate. On the other hand, and IMS rating certificate contains a lot of useful information about the seaworthiness of a particular design, such as its angle of positive stability and an approximation of its vertical center of gravity and buoyancy.

Jeff
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PHRF Interpretation

If I owned the boat to sail and get where I am going fast than I would want a lower number.

If I was in a PHRF sailboat race and I wanted to win I''d want my boat to have a higher number so I''d get more time on the handicap.

The number are mostly relative, but they relate to ''seconds allowed per mile". So lets say I have a 150 rating and you have a 145 rating, and lets say we are in a 3 mile race. If you are over the finish line 14 seconds before me I would win the race because I would be allowed 5 seconds a mile and at 3 miles I would get a 15 second allowance over you (you would get what they call "line honors"). If you finish 16 seconds ahead of me then you win the cup and hold the "line honors".

the numbers are relative seconds per mile, but they don''t really work out that way, because there are some "super speedster" Maxi boats that actually have ratings of 0 and negative numbers.
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PHRF Interpretation

My boat is over 30 years old. All wood ( except the hull ) and has a perf of 295 !

Wanna race me ?

Actually if it is blowing 10 - 15 knots I do have a chance, as long as I dont screw up.

Thorsten

The higher the number the "slower" the boat.
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PHRF Interpretation

You have the number mechanics down correctly, but some clarifications may help. First higher numbers per se are not generally preferable to low, what a racer wishes for is a boat that will sail faster than its rating - which is hard to find since the rating is purely subjective, based on the opinions of a board of very experienced racers. If a boat SEEMS faster than its rating, then they simply give it a lower number until the preception goes away. What a serious racer should want is a boat that sails well to its rating, whether high or low.

Line honors go to the first-to-finish boats, ratings being ignored. Handicap honors go to boats wining based on their times adjusted by their ratings.

You don''t need to buy a maxi boat to get into negative numbers, in New England a Farr 36 can get you to 0.

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