Here's a question for you handicap whizes. I understand the portsmouth numbers are adjustments for time. You take your elapse time, multiply it by 100 and divide it by your portsmouth rating (hence the lower the rating the lower the divisor and more time is added to your elapse time). BTW, the Thistle is the scratch boat in this system, having a portsmouth number of 100. This is a straight percentage thing; if my rating is 5% lower than another boat's, I have to beat that boat by better than 5% on time to win.

My question: How is PHRF rated and is there any feasible way to convert from one to another? I've heard of "minutes per mile" but don't understand what that means.

David
H20

I think there is a table of some sort out there, there is a guy at the local yacht club that has one, Unfortunately, I am completely devoid of usefull information as I have no idea what the thing is called, nor do I know how to contact this gentlman. At least I can tell you that I am 90% sure there is a way.

Generally speaking there IS a conversion between the two. However, PHRF is a rating that is called Time-On-Distance...AND it is adjusted to what region of the country you are in...

To convert from Portsmouth to PHRF:

PHRF = (Portsmouth - 55) * 6

To convert from PHRF to Portsmouth:

Portsmouth = (PHRF / 6) + 55

Remember, these will give you a ballpark estimate, NOT an actual number as PHRF varies greatly...I sail on an Olson 34 which has a PHRF here of 108. But out in California, it's rating ranges from 105 to 112. Using the conversion above, I come up with a PHRF of 123 for a boat that should be a 108 PHRF...

While I'm on the subject, just what does "DPN" mean? And, as Josh said, what does PHRF mean? I've been carrying these questions around for years. Help a guy out.

David
H20 with questions.

D-PN - Dixie Portsmouth Number
PHRF - Performance Handicap Racing Formula

They both suck

Ding

Ok..
I will rise up and stir the pot...

What would you prefer to use for racing similar but not identical boats.

Mark

There is also a "Time on Time" flavour of PHRF which works like PN.

TOTCorrected = Elapsed*A/(B+Rating)

Different clubs use different As and Bs; constants, not specific to the boat.

Time on Distance PHRF being:-

TODCorrected = Elapsed - Rating*RaceDistance

http://www.ussailing.org/phrf

Has anybody (Wouter ?) got the inclination to do an experiment? Take 1000 (say) sets of results and score them all with Texel or ISAF and DPN. Compute something like the the percentage of competitors across all events at which the results are the same - it could be 0% (I would guess not) but if it's something like 10% then perhaps the effort that goes into maintaining DPN (and other national equivalents like UK PN) is wasted in a cat context.

Then take the ISAF or Texel formula and simplify it to a point where, similarly, the first 10% (say) of results are the same. Use that for cat racing. It may be that no simplifcation is possible... The simplification would need to be future-proofed; i.e. if it just so happened that the formula could be defined in terms of boat length, it would be dodgy to actually use that 'cos it could be manipulated, but surely we can dump board area and the like, especially since the formula has crew weight in it, which is always 75Kg regardless of the crew weight!!

Mark,

I used to think it was better than not sailing at all. Now I almost couldn't be bothered. If you are sailing a handicap race then yes technically you are racing, but as far as I'm concerned you are just on a fast day sail.

I'd rather sail a boat I don't really like and sail one design rather than sail a boat I love and sail open. Right now I have the best of both.

Ding


I-20 #266

I always thought that DPN was for Default Portsmouth Number, as in what you use when for whatever reason you don't use the wind corrected numbers.

As far as PHRF goes, one thing that seems to enter into it is a political factor from the people that maintain it for the various regions.

As far as handicap racing in general goes, it seems to be a great way to build up participation. Yes, one-design is going to give you a better test of skills adn ability to keep your boat tuned to some nth degree, but as evidenced from the popularity of week-night PHRF racing for monos in our area, there's a lot of people enjoying this type of racing.

It's working for our Fleet. Weeknight racing using DPN. While it's not as pure as OD, we've gone from an average of 5 boats on the line to 15 over the last couple of years. That's on an every Tuesday night basis. Our high has been 20. Now within the boats on the start are various groupings of same-class boats that can bash on each other as well as everybody else.

But the thing about it is that the handicap racing we do on Tuesdays is not the end of the involvement for racing for our skippers. I have always felt that strong clubs such as ours can feed the other racing in general, be it OD or handicap, bouy or distance. Out of our club the I20, H20, A-Cat, and N6.0 classes have more presence and can gain in strength.

Not everybody wants to join in all of the various types of racing, and you'll go crazy trying to convince them all they should do one form or the other of racing that somebody deems superior. But if you can get (and increase) a large enough pool of sailors in some common ground, there will be a percentage that will go off and fill the other niches as well.

PHRF seems to work well for the monos - but you get the same carping and bitching about ratings that you'll get with any handicap racing from the people that like to carp and bitch. My understanding is that committee somehow knows the distance of the courses, and that feeds into the calculation of finish times.

D in DPN does stand for "Dixie". Jamie Diamond enlightened us on this tidbit in another thread on here a little while back. He provided this link as to the history of Portsmouth http://www.ussailing.org/portsmouth/section_i.htm

Hi David Ingram

I am curious what the turnout is for your I20 fleet in the regattas on your schedule and how it breaks down into buoy's racing and distance racing.

I know of only one class that can count on 10 or more boats at the regattas on their schedule. (Hobie 16's in the Mid Atlantic.) The Hobie 17's are pretty good in the mid atlantic ... but I would not bet money that they get 10 or more boats at every regatta on their schedule.

I saw that you had 10 boats at St Augustine. What other buoys events get 10 I20's out there?

My point is unless you choose to race one of these two boats... EVERYONE ELSE is damn near match racing within portsmouth racing under handicap. CBYRA, the big boat organization on the bay, wants to see 10 boats in a start to call it one design... They highly recomend smaller fleets race in the approriate PHRF band and get those numbers up in order to foster compettion. Makes a lot of sense to me!

Take Care
Mark

The H16's are the only fleet that consistently get a class. The I20 & TheMightyHobie18 fleet do okay, we can usually get 5 or more at specific events.



Makes a lot of sense to me too. If you have to sail handicap then that's a good way to do it. My point is... I hate handicap racing! It's a hassle to travel, spend a crap load of money then end up sailing open. I can think of a lot more ways to spend that money.

When the I20's can't field a class at bouy regatta's then I see a F18, H16 or maybe an MC Scow in my future. I'm done racing open!

Ding

Hi,
PHRF is a time-on-distance rating. (sec/mile). It varies a little depending on region because of varying wind and sea conditions and the courses run there. I am on the council for my region, which I believe is extremely factual with no politics (we meet once a month with much data going back and forth).
Many(if not most) PHRF fleets convert this into time-on-time in various ways. It seems the most common is:
TCF=550/(PHRF+650).
This is the Time Correction Formula and is multiplied directly by the elapsed time to get the corrected time. Others use different values for the denominator - see http://www.ussailing.org/phrf/TOT.htm
which is an excellent article by John Collins.
Be careful about comapring Portsmouth yarstick from mono's to cats - this does not work. The 100 for the Thistle should not be compared to the 92.4 for the Hobie Wave, for example.
To convert mutlihull D-PN to PHRF is tricky. I've tried several formulations. Here is one I made up:

PHRF = [(650 x DPN)/75] - 550

This makes a Hobie 16 PHRF = 110 sec/mile and a "Classic" Olympic Tornado PHRF = 3. That means the Tornado owes the Hobie 107 sec/mile or, in PHRF time-on-time, about 10 minutes an hour.

According to Portsmouth Yardstick, with the Hobie at 76.1 and the Tornado at 63.8, that's about 11.5 minutes an hour.

Seems to work OK in that regard and also very crudely against the monohulls. (though it shouldn't be used that way - but it's nice to have some point of reference). I handicap for a race that has 120 mono's and sometimes 15 cats, and this seems to work OK, though we only score boats in their own division, it's still nice to compare.

Steve

Hi David
One more try here (grin)

The following 15 boats:
NACRA 20 Claus Schnabel Rick Olt 306
NACRA 20 Mark LeBel Karen LeBel 495
NACRA 20 alex lefur chris berger 625
NACRA 20 Kurt Korte brad winquest 254
NACRA 20 Harold Burns Frank Burns 462
NACRA 20 Wes Wilcox 253
NACRA 20 Bruce Binger
Tornado (Intern.) Robbie Daniel Gary Chu US834
Tornado (Intern.) Chris Blake
Tornado (Intern.) Craig Jefferds ISV3
Tornado (Intern.) Kurt Wellenkotter Steve Gornick US 741
Tornado (Intern.) Chris Tuckfield Nina Barlow 812
Tornado (Intern.) Martin Malcheski Benjamin Malcheski 824
Tornado ? Josh Garrett Bobby Garrett
6.0NE Dave Reese Amos Cushway 420

are the current list of 20's with spins attending the Catfight this weekend! A turnout of 15 20 foot spin boats will be the top turnout for a buoy's race this season IN THE COUNTRY.

So... A perfect race is sailed by all teams and they finish in a dead heat at 60 minutes.
Boat.... Rating.. Elapsed time to win position.
Nacra 6.0 NESp 60.3 60.00 0.00.00 1.0
2 Supercat 20 tall rig 59.5 60.00 0.00.48 2.0
3 Nacra I 20NA 59.2 60.00 0.01.06 3.0
4 Tornado 59 60.00 0.01.18 4.0

(In New England... they race the Nacra 6.0 against the I20 even up and the Nacra will win the race and i used Bill Roberts SC20 rating in a seperate thread! )

If you use windspeed numbers... the I20 is faster in the light to moderate stuff and with breeze on the Tornado is faster

Bottom line... the I20 and the Tornado differ by 12 sec an hour... Watching the Olympic racing on Bravo indicates that the best in the world are finishing over 10's of minutes ... not seconds in one design boats.

In my book... the upcoming race is FAR BETTER then the smaller one design divisions you could create. Yes it's portsmouth... but on the race course... I will be damned if you can tell the difference, (I loose 12 sec an hour when I sneeze!)

I propose that before the racing scene on 20's disolves.... you bend a little on the one design desire and market and participate in racing of 20's with spin...

Take Care
Mark

But you and I both know that most regattas don't draw the numbers the Cat Fight does therefore racing within tight bands is not feasible most of the time.

I absolutely never want to hear someone tell me “again” that I brought a knife to a gunfight. I've been in this game a long time (maybe too long), and the longer I do it, and the more I learn about the handicap system the more I realize it's a POS and an unhappy compromise.

You compare the T to the N20 and say they are only 12 seconds apart per hour. Mark gotta call a BS on that. D-PN is a best guess and that’s it. The data sample used to create D-PN’s is so small that we are lucky the numbers work at all. I have absolutely beaten the living snot out of a team on a Tornado that should have easily done the same to me. And I didn’t beat them because I was unusually brilliant that day; it was because we had conditions that favored the N20 and not the T. To me that aint racing!

You say there are 10’s of minutes in difference between the T’s finishing at the Olympics, well let’s be honest, what you have is the best from each county and not all countries are created equal when it comes to sailing talent. I’m quit sure there are many sailors in the world that are far more talented than many of the sailors represented at the Olympics. Is it the best in the world? Technically yes, is it the best of the best… not by a long shot so for there to be large spread in finish times, it’s no big surprise.

At the N20 Championships in St. Augustine the finishes were very tight in the top five and the fleet was fairly compact excluding those that made very large errors (catching the mark). That’s the kind of racing I want. I don’t want to race somebody’s number, I don’t want someone to tell me it wasn’t my boats day, I just don’t need it!

If handicap racing brings the numbers then great, keep up the great work. But, personally it doesn’t interest me, I’d go fishing rather than sail open.

Dave