PHRF Certificate (and PHRF Info)

Elise just received her 2007 NC PHRF Certificate. Her rating is 129 seconds/mile (like regular Express 27 ODR). Performance Handicap Racing Fleet certificates are one way of adjudicating race that is not One Design (eg, not all the boats are of the same type). One Design racing is regulated by class rules to ensure that the winners win thanks to their superior sailing skills, not because they have more money and bigger sails.

Some races may be open to different types of boats. Typically, these boats will be arranged by class (roughly the same size/speed boat will compete together). Those are more tricky to handle tactically because some boats will be naturally faster or slower than your boat. Hence the need for a handicap system.

Sailboats racing under a "handicap system" have a function applied to their elapsed time, producing a "corrected time," and the boats place in corrected time order. This function, which differs among systems, attempts to fairly represent speed differences among boats.

For example, an Olson 25 is slower (on average and based on past performance) than an Express 27. So if the Olson 25 and the Express 27 both cross the finish line at the same time, the Olson 25 did a better job since they started worse off to begin with and at the same time as you did on the Express (obviously this example is 100% theoretical ;-)). The quality of their job is also proportional to the distance of the race. If you are slower than other boats, the distance between you and faster types will increase with the length of the course. This is why the handicap is calculated per mile and acts as a time multiplier. In this particular case, even though the two boats finish at the same time in real time, the Olson would win on corrected time because the Express will owe her time. In most PHRF races, you will see both times in posted results: Actual and Corrected. The corrected time is calculated based on the actual finish time and the boat handicap (rating * distance of the course)

(if you want to illustrate this, you can do this experiment with a friend. You are allowed to run but your friend can only walk. Try to run as fast as you can and ask your friend to walk as fast as he/she can on the same itinerary. Vary the length of your race and measure the distance between you and your friend when YOU cross the finish line)

PHRF (pronounced "perf") is Performance Handicap Racing Fleet.

PHRF ratings are assigned based on past performance of similar boats. So Elise's rating is the number of seconds per mile she is supposedly slower than a theoretical boat which rates 0. Most boats you are likely to sail on rate somewhere in the range of about 50 to 250. All ratings are multiples of 3 seconds/mile (i.e. the next faster rating than 171 is 168). I think this is done as a recognition that the rating process just isn't accurate enough to justify rating boats to 1
second/mile resolution.

Typically, a certain type of boat is given a stock rating based on past experience. Just to make it a bit more interesting, ratings vary somewhat depending on location; each YRA (Yacht Racing Association) can assign its own rating to a class of boat depending on their local experiences and conditions. For example, a good heavy air boat would rate faster in San Francisco Bay, than in Long Island Sound.

On top of your regional stock rating, there are a variety of standard rating adjustments depending on how your boat is rigged. The standard PHRF rules allow you to have a 153% genoa. You can carry a larger sail, but take a rating penalty for it. Likewise, you can chose to not
carry that big a sail and get a rating advantage. Having a non-standard keel, extra tall or short mast, a fixed prop (the stock ratings assume a folding or feathering prop), extra long or short
spinnaker pole, etc, all result in rating changes. Some boats have several stock ratings for different common variations. For example, there are 4 configurations of J/29's; masthead or fractional rig and inboard or outboard.

There are two flavors of PHRF, Time-on-Distance (TOD) and Time- on-Time (TOT). TOD is the more traditional and easier to understand, so let's start there. In TOD, you get a handicap equal to the length of the race course in nautical miles multiplied by your rating in seconds/mile. Thus, for a 6 mile race, a boat that rates 120 would get a 720 second handicap, i.e. her corrected finish time would be 720 seconds less than her actual time to complete the race. What people tend to do is think not so much about the actual rating, but rating differences, i.e. if you rate 120 and the other guy rates 111, he owes you 9 seconds per mile, so for a 6 mile race, as long as he
finishes less than 54 seconds in front of you, you will correct over him and win. Most PHRF races that Elise will do will be of that type. (I don't believe that I have sailed with the other type at all). So the formula for PHRF is to use the rating, in s/M, multiply it by the length of the course and subtract this number from the boat's elapsed time to get the corrected elapsed time (in seconds).

The other flavor of PHRF is Time-on-Time (TOT). In TOT, it's not the length of the race course that matters, it's the amount of time the race takes. To do TOT, first you have to convert your normal rating, R, in seconds per mile to a factor, F. The formula to convert R to F varies from place to place, but it's typically something like F = 600 / (480 + R). Actually, it's really something like F = 600 / ((600 - Rav) + R), where Rav is the average rating of all the boats in the fleet in that area. For reasonable values of R, you get an F which is a number close to 1. For example, a J/24 rating 171 has an F of 0.9217, while a Newport-41 rating 108 has an F of 1.020. To score the race, you take each boat's finish time, subtract their start time (giving their raw elapsed time) and multiply by their F, giving their Corrected Elapsed Time (CET). The theory behind TOT is that in a slow race (i.e. light wind), the boats tend to spread out but since the
amount of time each boat owes the others is fixed by the length of the race course (in TOD), slow (i.e. light wind) races tend to favor the faster boats.

On of the problems with TOT is that there is no universally accepted formula for converting R to F. With the sort of formula used above, you can argue about what should be used for Rav. Some people think we should calculate an Rav for each division, for example. Some people think TOT
is a total crock and want to go back to TOD.

Ratings are assigned by a committee of the local racing authority, formed from representatives of the member clubs. In our case, it is the Yacht Racing Association of San Francisco Bay. These ratings are somewhat subjective and I am sure that many people keep arguing over the accuracy of PHRF rating. A member may appeal a rating, presenting evidence, such as race results, which supports the appeal. The local committee's decision may be appealed to a committee of PHRF handicappers from all over the country.

Still, they are useful in that they allow us to have a lot of fun in other types of events. I don't believe that we will be contesting them!

For professional non One-Design races, often a more elaborate and theoretical handicap system (based on measurement) will be used. The stakes are a bit higher :)