PHRF Ratings Explained

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Nicholas

How accurate are PHRF ratings? My first thought is that they are caclulations that put different vessels on some equal playing field for times over a race course. How can anyone properly come up with a number that works...I mean really? Comments
 
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John Burns

They can't

I am involved in club racing with the only reward monthly bragging rights. However, the competition can get pretty intense with PHRF's the deciding factor in most race standings. For the last year or so there has been a lot of debate about the PHRF numbers assigned to various boats. I have concluded that assigning PHRF numbers is a fluid process and can only be done under the cover of darkness by the Wizards of PHRF Fudgery.
 

Alan

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Jun 2, 2004
4,174
Hunter 35.5 LI, NY
A great equalizing factor is to subtract 6 seconds from the first place boat's PHRF rating, 3 seconds for 2nd, and 1 second for third for subsequent races. This adjustment helps to prevent the same boats from winning race after race and gives others a shot at trophies.
 
Oct 26, 2005
116
Oday 28 Detroit/Grosse Pointe Park (O'Day 192, O'Day 28)
PHRF

There's also some local variation. On Lakes St. Clair & Huron, we rate 126 (C&C 35 Mk 1) and on Lake Erie we're 123. Also, adjustments can be made after a rating has been assigned if a boat wins too often. The newest trend seems to be IRC http://www.ussailing.org/offshore/irc/ There's some secret formula in a box in Ireland - you hire a boat measurer to come out and measure a bunch of stuff, they send it in, and you get your number back. Each boat has to be measured, so the numbers can be different even between boats in a one-design class. PHRF works on the total mileage of the course, IRC works on elapsed time. We'll see what happens this year in the Port Huron-Mackinac Race.
 
Jun 4, 2004
844
Hunter 28.5 Tolchester, MD
PHRF Reliable Comparison?

I have had a PHRF number of 174 on my Hunter 28.5 since new in 1986. It is important to note that that base rating on the Chesapeake bay assumes a folding prop, a 155% max Genoa, sails in good condition and presumably a clean faired bottom. Sailing against other boats in similar condition with similar equipment and presumably similar crew ability, we've sailed enough close races to consider the 174 a fair rating. Any similar deep draft 28.5 that has sails in mediocre condition, a roller furler, a fixed prop,or a mediocre bottom job will,in my experience, not sail to the 174 rating. A lighter boat (say a J24 at 168-174 will be stronger in light air; while a heavier boat like an Alberg 37 (PHRF of 174)will be stronger in heavy air.
 
Oct 25, 2005
735
Catalina 30 Banderas Bay, Mexico
Handicaps don't work .. :)

Handicapping systems don't work very well. They never have. Of all the systems in place. PHRF should be about the best for "normal" racer/cruisers. The problem can be seen by looking at the results in One Design races. If the difference between first and last in a one-design fleet is 10 minutes after a 6 mile/1 hour race that means that the last boat is 50 seconds a mile slower than average and the winner is 50 seconds a mile faster than average. No one-design boat has a PHRF rating 50 seconds a mile faster or slower than another boat in the same class. This means that the variation in crews can easily make a 50 second per mile difference in the same boat's performance. The best a handicap system can do is try to give each boat a rating so the entire fleet falls within the same margins that a one-design fleet does. PHRF is supposed to be based on Performance. If after many races one boat design is above average all the time the handicap should change to bring the results back to the fleet average. This only works if there are many races that include many boats of the same type. Comparing all boats to a J24 makes some sense. There are enough J24's on most areas to give valid results to measure other boats by. What most PHRF committees do is try their best to estimate the performance of boats that don't have a big enough data base to give a true performance rating. A good PHRF committee can do a very good job and the handicaps are as fair as possible. When boats with wildly different performance sail against each other handicap systems fall apart. No system rates 70ft boats and 24ft boats properly. Ratings within boat types are pretty good, like sports boats with a 20-30 second per mile range in the fleet. Racer/Cruiser types within 30-50 sec/mile brackets get fair racing under PHRF also. It's when you try to compare a 256 sec/mile Santana 22 to a 12 sec/mile 50 footer that it all comes apart. No system handicaps the two boats fairly. Bottom line, a good crew on a well prepared boat can probably sail 20-50 sec/mile faster than the PHRF rating and other boats and crews will be 20-50 sec/mile slower than the rating. In other words if one 30ft production boat has a 6-12 sec/mile slower or faster rating it doesn't mean much.
 
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