Phrf ?

JohnShannon · Jan 27, 2011

No expert, but as I understand it, your PHRF compares you to other boats. You have PHRF of 219 my boat for sake of argument is 200. If we race I have to beat you by more than 19 seconds a mile in order to be proven the better sailor. So on a 5nm course you have to stay within 95 seconds of me.

The PHRF is based on observation, so you get different PHRF is different regions as local conditions would favor one design over another. Also somewhere on the internet some NA has a pretty funny take on PHRF. Notes that the local PHRF committees boats tend to rate high, also notes that your best PHRF racing asset is an incompetent partner who gets to race the boat half the time.

shemandr · Jan 27, 2011

I'm sure you know USSA's website has some info on PHRF - I'm not sure it will clear it up.
The comparison in speed would be straight line hull speed not speed going upwind and tacking. PHRF contains assumptions that your boat is optimized for racing with a clean smooth bottom, contains no extra weight, has good sails, competant crew etc.
I've never seen the PHRF related to 1 nm boat speed in seconds like you do, but I guess that would be mathmatically correct. I don't think it would be useful in dead recogning or cruise planning because cruising boats would have difficulty sailing to their rating with all the weight, the three bladed prop, casual sails etc. Also, fleet handicappers tend to be somewhat arbitrary in assigning rating numbers - it isn't like MORC or IMF or other more sophisticated ratings which are based on design parameters.

tommays · Jan 27, 2011

As said the numbers tends to be a WAG on many boats Vs a boat like my J24 which has had pretty much the same (174) number for the last 30 years

RichH · Jan 27, 2011

There's yet another 'handicap system' that many fleets use: The PortsMouth Yardstick System - a rating system that uses "time-on-time' calculations as opposed to the PHRF time-on-distance calculations
http://offshore.ussailing.org/Portsmouth_Yardstick.htm & ....
http://offshore.ussailing.org/Portsmouth_Yardstick/Tables_2010.htm
The 'advantage' of the Portsmouth system is that the 'rating' is also based on the wind strength at the time of the race. This handicapping system is typically used for comparing 'closely rated' boats.

Bill Roosa · Jan 27, 2011

Well you have to have some way of compairing them

The PHRF comes into its own when you see races to Brumuda and such. Everything from sailing dingies to maga yatches. Just because you come in first does not mean you win. In fact you can come in pretty far back in the pack and still win.

Bill1565 · Jan 27, 2011

Quoddy said:
What does the PHRF number mean?

B is
480 Heavy Air or all off the wind
550 Average conditions
600 Light air or all windward work

As mentioned, these numbers do not give you boat speed. They are used in converting PHRF Time on distance numbers to time on time numbers. Still relative to of other boats. A time correction factor(TCF) of 0.98 x 60 minutes elapsed =58.8 minutes corrected time. Beats 55 minutes x 1.07= 58.85 corrected time

Jalepeno · Jan 27, 2011

I don't race but here is a good explanation of PHRF:

http://en.wikipedia.org/wiki/Performance_Handicap_Racing_Fleet

Joe · Jan 27, 2011

Quoddy said:
What does the PHRF number mean?
B + PHRF, is the number of seconds it takes to sail a nautical mile in the expected conditions.
B is
480 Heavy Air or all off the wind
550 Average conditions
600 Light air or all windward work
This gives you the “perceived speed potential of a yacht”

Does this mean that a 4.7 nm course in “average conditions” could be expected to be completed in 1 hour, even though the distance with tacks and jibes is much greater than 4.7 nm?

wow...... where did you come up with that? PHRF is just a method to establish a handicap value between different boat designs for racing purposes. A PHRF rating is basically useless by itself.... The difference in boats' PHRF ratings is used to adjust their times when they race each other (as in the same race where conditions are the same). KISS

Prime Time · Jan 27, 2011

PHRF

The difference between 2 boats ratings is the time in seconds used to correct per mile.

Todd Smith · Jan 28, 2011

Re: US Sailing

Quoddy,

The simple version of PHRF uses "time on distance" scoring. "Time on time" is an extra complication that attempts to adjust better for light or heavy wind.

In time-on-distance scoring, the straight line distance of the course ( ignoring tacking, etc ) and the difference in ratings between boats is used to correct a boat's time. The time correction between two boats is:
time in seconds = course distance * ( slower rating - faster rating )

But I have never tried to use those speeds to predict a passage time. Use your far more detailed knowledge of your boat's capabilities to plan the passage.

MSN-Travelers · Jan 28, 2011

Quoddy said:
...

I was looking for some clarification of the above statement which is a quote from the site.
I am considering a race of some distance, 30nm, single handed and was wondering if I could expect, to even be able to finish in a reasonable amount of time.

I'm crew and don't know/understand all the formulas that enter into an assigned PHRF rating. I do understand how they are used as one of my duties is time keeper. The Milwaukee Bay Challenge series has a number of distance races each season. The sailing instructions for each race indicates the "Time Limit" for each boat in a given race.

As an example:
Race: Wind Point - Racine (a down `n back from Milwaukee to Racine)
Race Distance: 27.2 NM
Time Limit: 7 hours + 2 times boat's allowance

The boat is a Pearson Flyer with an assigned rating of 135. Our time limit for the race is 9.04 hours. (135 seconds * 2 / 3600 = 2.04 hours) With a 1000 start ... have to finish by 1902 in order to "finish".

While we have achieved speeds of 9 knots in good conditions, we use a hull speed of 6 kts for planning purposes. If we are 12 nm from the finish, its 1700 and winds are giving us an average speed of 3 kts (and dropping) ... it's time to drop the sails, crank up the iron genny and open a beer. We can't finish in the allotted time unless a miracle occurs.

You would use the same basic formula to determine if you can finish in a reasonable amount of time. Take into account your boat's average speed in a given wind and your ability to single hand over that time. Your personal endurance plays a bigger role than your PHRF rating.

I don't know where you sail. I have never seen wind speed and sea state used in scoring, just PHRF rating. In the example race above, the raw time is reduced by a boats PHRF rating (in seconds) * the race distance to achieve a "corrected time".

Same race example - Last year we finished at 16:00:50 after a day of moderate variable wind. Elapsed time was 6 hrs 50 seconds. Boat allowance was 1 hr:1 minute: 12 seconds (135 * 27.2 nm) Corrected time (elapsed-allowance) was 4 hrs:59 minutes:38 seconds. Correct times for all boats are then compared in each division and results posted.

We do a 69nm night race across Lake Michigan each year. Last year we finished fourth in our division, 1 second behind third place.

I hope this helps you understand how your boat's PHRF rating is used to determine your allotted time for a given race and how it might be used in scoring a race.

Cayennita · Jan 28, 2011

The 3 numbers used to change fro time on distance to time on time are derived from the existing PHRF numbers that have been assigned to the boats entered in a regatta. The race committee will chose the boat that is in the middle of the range of all boats entered and will assign a number that will give as close as possible a rating of 1.000. The number could be anywhere from 500 to 600 (a constant). The formula being constant number (650) over the constant plus your PHRF number. The differential between boats will be somewhere in the 3.6 seconds per hour for each .001 differential. Obviously this can not be used on pursuit races. A boat with a rating of 135 PHRF in a medium air race with a mid number of 550 will then be = 650 / 550 + 135 = .929. Google PHRF time on time articles. It's all there

s sauer · Jan 29, 2011

Contact Race Committee?

I would expect that the Race Committee has figured the course distance and anticipated time for the smallest boats and the prevailing wind conditions in that area at that time and set a cut-off time -- call them.
We used to do PHRF time on distance club races in the mid Chesapeake and had a typical five hour cut-off; but as an example wouldn't set a long point to point cruiser's race where light air and adverse tides would be expected. Round the marks, windward-leward and triangle courses are more easily predicted IMHOP.

Jerry Clark H356 SV Persi · Jan 29, 2011

Cut off time at Kentucky Lake Sailing Club Regattas

At our regattas, we group the boats into Jam A, Jam B and Spinnaker. If we have enough for a class, we will have a fourth group for that class.

A PHRF around 168 is generally the cut-off for Jam A and B. Below 168 would be Jam A, 168 and above, Jam B. The 168 is not a hard and fast rule and we look at the boats entered and try to balance the fleets (A & B) into pretty much equal numbers of boats.

Our cut-off on a distance race is 2 hours after the first finisher in a class. Longer tha that and you get a DNF. Around the buoys races cut-off generally is 45 minutes after the first class finisher. If the wind just gets real low , we move the finish line to the first boat and finish the class, with 45 minutes then move again to the next class if we have to. Moving the finish line is not done often but we have had to do it.

We use a program called RACESAIL to score and use Time on Time. The parameters of the program have us enter average speed during the race, so wind is a factor in the scoring. The program scores as per the parameters using the Portsmouth method.

shemandr · Jan 31, 2011

RichH said:
There's yet another 'handicap system' that many fleets use: The PortsMouth Yardstick System - a rating system that uses "time-on-time' calculations as opposed to the PHRF time-on-distance calculations
http://offshore.ussailing.org/Portsmouth_Yardstick.htm & ....
http://offshore.ussailing.org/Portsmouth_Yardstick/Tables_2010.htm
The 'advantage' of the Portsmouth system is that the 'rating' is also based on the wind strength at the time of the race. This handicapping system is typically used for comparing 'closely rated' boats.

Thanks for these links, RichH. It seems like an interesting alternative to PHRF. I'm not sure it would work for us because we have very dissimilar boats ranging from J-22's to a Catalina 27 and sometimes a Hobie 33 in the spinnaker class and in the cruising class a Stuart Knockabout to a Santana 30/30 to my Hunter 356.
I am going to request a review of this rating system by our race committee to see how it would work - and I'll end up being the reviewer.

shemandr · Feb 2, 2011

Question: I cannot find anywhere what the paratheses mean in the handicapp numbers. Can anyone explain?