US-DPN boat modifaction calculator

[hoofhearted]

Hi, everyone.  Does anyone out there no of an online calculator that will calculate Portsmouth ratings for boats with modifications? 

For example, if one has a sloop rigged boat, and sails with main only no jib, no spinny.  The Yardstick has formulas in the book, however for a slacker like myself who is horrible at math, it is a headache.

Anu input would be appreciated.

Thanks in advance.

 

[The Q]

I thought they were dropping D-PN in the USA..

 

[hoofhearted]

US Sailing is co=partnering with RYA.  RYA Portsmouth Yardstick Race Analysis (pyonline.org.uk) 

Though still looking for a calculator.

 

[Foredeck Shuffle]

US Sailing is co=partnering with RYA.  RYA Portsmouth Yardstick Race Analysis (pyonline.org.uk) 

Though still looking for a calculator.

US Sailing abandoned Portsmouth.  Didn't bother to convert any ratings to RYA Portsmouth and left it to the membership to take care of.  There is a portal at RYA but absolutely no work was put into it by USS.  The RYA Portsmouth also does not have a wind rating calculation so performance of a boat at different wind speeds is not included.  It's a disaster of a decision.  USS was sitting on decades of data and decided to do nothing but forget that anything other than one design small boat sailing exists in the US.  They might as well have decided to use PHRF for a poor a decision as it was.

 

[Foredeck Shuffle]

Hi, everyone.  Does anyone out there no of an online calculator that will calculate Portsmouth ratings for boats with modifications? 

For example, if one has a sloop rigged boat, and sails with main only no jib, no spinny.  The Yardstick has formulas in the book, however for a slacker like myself who is horrible at math, it is a headache.

Anu input would be appreciated.

Thanks in advance.

Find someone at the club willing to help do the math.  Having more than one person work over the numbers will ensure that you are giving the new rating a fair comparison with the existing ratings, which is important to fair sailing.  Doing the math will help immensely with your local fleet when new designs show up or other boats are modified.  It's not easy but it might be the best dinghy rating system yet conceived.

 

[maxstaylock]

The RYA PY system is a simple time on time system based only on past performance.  Most clubs submit their race results every year, so the number gods can work out which classes seem to be winning too much, or not enough, and so modify the number list accordingly.  No system is perfect, some boats do better on the coast, some inland, some do better in light winds, and some in heavy airs, but every dog has its day.  It's easy to run the races, and the scoring system is a universally used computer program.

Classes need to be sailed in class measurement trim, so no leaving weight correctors behind, or using oversize kites.  You can beg your club for a better handicap, maybe if you have an older uncompetitive boat, but then if you ever win, it's meaningless.  If you have a non class boat, you could suggest a number to your club, but again, winning becomes meaningless.  Clubs are encouraged to modify their PY numbers to suit local conditions, but most don't, to avoid accusations of bias.

Because of the lag in the system, development class boats and restricted classes can do better than strict one designs.  Olympic class boats have punishing handicaps, because of the standard of sailors pushing the number down, so no average sailors race olympic classes in handicap.  When a class changes to carbon mast, or epoxy construction, they get a bandit number for a couple of years, till the handicap catches up with them.  Etcetera. 

By contrast, in the UK, Catamarans sail to a measurement rule (SCHRS), so you can work out a handicap for a greater number of variations, weight, number of crew, sails used etc.  It has the advantage of letting you race anything, established class or not, but suffers the usual built in measurement system issues, if you don't race the type form (Formula 18), or very very similar, then you will always be beat, as non Formula 18 features, like lightweight construction, or no kite, or singlehander, are punished disproportionally.  I think the dinghies performance handicap system (PY) is better, but it does rely on lots of race results.

So, in a perfect world, all nations would adopt the same system, there would be even more source data, and the results would just keep getting fairer.  

Handicap racing is of course always a poor relation to class racing, but it's still fun, and the best sailors still usually win.

 

[Xeon]

Spot on and well explained . Totally agree 

 

[AnIdiot]

Spot on and well explained . Totally agree 

Seconded. Good summary of a good system. Perfect? No. Good enough? Yes.

 

[JimC]

Its worth adding that wind strength adjustments - and for that matter water type adjustments (because confined gravel pit or open sea can be as big a factor) - are impractical because of lack of data. Yes you could do such things for say the ten most popular classes if you could persuade the clubs to gather the data, but at the other end of the scale there are already many somewhat active classes that fall off the list due to lack of data. Divide the data in three wind bands, for instance, and probably a good two thirds of classes would have insufficient data for one band or another.

You may ask how D-PN did it. That's an excellent question. The stories I've heard about how D-PN numbers were arrived at I regard as barely credible, and *if* true the calculation basis claimed would not fill me with confidence.

You can get away with a lot with handicaps because they make far less difference than most people believe. The spread of finish times in a typical championship fleet in the UK seems to run around 20%. Its always an interesting exercise, now we have computer results calculation, to rework a series with whatever a complainer thinks is the right handicap for his boat. It rarely makes any great difference, and frankly who can judge whether Jane should have been 10th and Bill 11th overall, or vice versa!

Incidentally these days I'm of the opinion that the "every dog has its day" nature of single number handicap racing is a strength rather than a weakness. I've noticed a lot of club one design fleets collapse when a hierarchy forms and the results get too predictable. With single number handicaps you need to sail well and be in a suitable boat, so the race wins are shared with more people. Same names get the series prizes, but more people get to go home happy after a day that suits them.

 

[The Q]

I agree with Jim C, I'll add a note that the RYA says in their instructions you can modify the handicap to suit your local conditions.

Though this does bring back the possibility of people claiming it's unfair, so most clubs don't. 

I know of no clubs in the UK using the RYA PN  that change their handicaps here for wind speed, it's assumed over the years it will even out, so a quiet wind year, the lightweights might win, in strong wind years the heavy weights will win (in boat terms)

At my Summer club some classes of boat have different handicaps depending when sailed on the river or the Broad, I know of some clubs that have changed the handicap of certain classes because they know with many sailing there, the overall class over or under performs.

The Winter club sticks to pure RYA numbers, generally that doesn't favour planing boats like the Laser on a limited space river, but does favour something like an Enterprise which tacks well and it's overall RYA handicap is less influenced by planing in open waters.. That is solved by there being a single hander trophy.. as well as an overall dinghy trophy..

 

[Foredeck Shuffle]

For every anecdotal story about the validity of the NA-PN (formerly D-PN), there was a significant body of work that has unfortunately died out with the former managers of the system.  I've looked for the paper work a few years ago and it ran into dead ends as the owners of the data have passed on.  US Sailing may have something, but in the recent past I could not get a response for data.

The problem with allowing a rating system to be reduced to "every dog has it's day" is that most areas have a prevalent condition.  My own anecdotal evidence based upon NOAA reports is that most of the US East Coast experiences light air on most days.  Compare that to most dinghies which are designed for a middle ground that does not inherently try to kill the sailor.  I'm ignoring the prevalent US one designs as most are fairly nontechnical and unable to power up or down in a substantive manner when compared to modern designs.  In an area with light wind it pays to select a very high SA/D and low D/L boat and just stay ashore when it blows 15kts+ because that wind range represents less than 10% of race days.

From running a fleet and managing the scores, I always ran the finishes with base ratings as a side item because I had heard people make the argument about it not making a difference.  The difference was always enough to change a few scores and it would have changed the season.

 

[eyeshotpar]

US Sailing abandoned Portsmouth.  Didn't bother to convert any ratings to RYA Portsmouth and left it to the membership to take care of. 

I hope not. I hope just taking a long time.

 

[JimC]

I agree with Jim C, I'll add a note that the RYA says in their instructions you can modify the handicap to suit your local conditions.

In addition there's a software tool provided by the RYA as part of the system which calculates numbers based on the club results, and gives a confidence factor for the proposal. In practice its only really useful for classes with a fair number of boats and results, but it all helps.

For single boats one can always fall back on the good old "calculate a handicap that will give Fred the same series place as he had with his old boat" which will disappoint Fred if he was thinking his new craft would waft him to the front!

 

[The Q]

In addition there's a software tool provided by the RYA as part of the system which calculates numbers based on the club results, and gives a confidence factor for the proposal. In practice its only really useful for classes with a fair number of boats and results, but it all helps.

For single boats one can always fall back on the good old "calculate a handicap that will give Fred the same series place as he had with his old boat" which will disappoint Fred if he was thinking his new craft would waft him to the front!

That's what I'm hoping with my new one off boat,, We were normally in the top three with the old one...

 

[Foredeck Shuffle]

I hope not. I hope just taking a long time.

I stopped trying to communicate with USS two years ago but from a response from a writer at Sailing World who wrote an article concerning reviving US-PN, he communicated that there are no volunteers working on US-PN nor had their been for nearly two decades.

As much as we want to vilify organizations such as USS the truth is always that there are few volunteers.  I volunteered for a YRA for almost a decade but it took nearly two years for them to remove my access after I had ceased to be active.  Watched the same with others that tried to disengage after being a volunteer for too long.  I can search and find too many threads here and other forums about how the YRA I was volunteering for was not just incompetent but behaving fraudulently with member dues.  Meanwhile when I joined my first major task was to get the organization out of the red.  We only had 1/3 of positions filled so that is most of what we did for three years.  Online it sounded like we were taking sailing charters with the money, that we didn't have.

There is so much money surrounding the sport of sailing but so little is used to run the organizations to support it.  I cannot speak for USS, but I'm familiar with similar stories at YRA''s up and down the east coast US and the Great Lakes.

On a positive note the YRA I was at is now a little bit cash flush due to the efforts of those of us who inherited a bankrupt organization.  The current management is full of non-technical types (my era was flush with them) who are more into sales and marketing and they have taken that extra cash and figured out ways to pump it directly into fleets and the membership in ways that entices more people to join and/or renew.  To me who is at this point burnt out from volunteering for different sailing organizations for two decades, this was the best thing that could have happened.  My team was good at righting the ship, but this new team is good at putting that ship to good use.

I get that those using RYA-PN are defensive.  It's theirs, for them it has worked.  But having spent time reading how to apply US-PN to race results of new boats and how to take a new boat and compare it to old boats to get a base rating that then must be adjusted as results come in, the wind ranges included, it is one of if not the best rating system out there.  I'm including every keelboat rating rule I have studied.  Those wind ranges are what level the field and because new designs have larger performance ranges depending upon wind speed and apparent wind angle, to ignore wind range modifiers is naive.  Boats, especially dinghies, sportboats, and multihulls, have always performed very differently in different wind ranges and modern versions of those boats are becoming more extreme in the range of performance they exhibit.

I miss OD sailing but I moved away from a location where that is possible.  If the alternative is to sail a flat rating system that is no better than PHRF, I will probably move on to cruising.  Fortunately/unfortunately, my current club is hyper conservative with a good dose of "not invented here" ism so I doubt they will take up RYA-PN within my lifetime.

 

[Xeon]

I think you will us users of rya py are not defensive. It’s just most of us are happy because it works for most people most of the time. It works because of the volume of raw data plus its simple to use . 

If you don’t have that raw data it doesn’t matter what system you use. 

 

[Foredeck Shuffle]

I think you will us users of rya py are not defensive. It’s just most of us are happy because it works for most people most of the time. It works because of the volume of raw data plus its simple to use . 

If you don’t have that raw data it doesn’t matter what system you use. 

You are very correct.  This was the purpose of contacting USS, I wanted their data.  I have no idea if anyone at USS has it anymore and that would be extremely unfortunate.

 

[fastyacht]

We actually used the US portsmouth including w8ndranges very succrssfully both at my town dinghy racing before it evaporated, as well as at my club. The latter is river racing so I would say more of a crap shoot but it was very effective in the triangle courses.

The idea that all the data is lost and the whole thing headed for the scrap heap is, frankly, more maddening than almost any oyher nrws or rumor aboit USAiling I jave ever heard.

Say it aint so...