Category Archives: PHRF

Hotlaps tops 300

Posted on February 25, 2013 by | Leave a comment

hepurn thurs

Woots! Kudos to LucyInThe Sky Afarensis; yesterday she posted lap #300 to the Hotlaps spreadsheet! She hit that tercentennial ceiling in real style too, by adding a new boat class to the list: The ACA Racer Tiny. :-)

On the six Hotlaps courses to date, a total of 54 skippers have sailed 305 laps in 33 different boats. Wowzers! Here’s the current list of skippers who did all that sailing, colored-coded for the spreadsheets:

skippers 54

And next, here’s a copy of the current, active spreadsheet for the Plum Gut course. Individual lap scores are arranged in columns based on boat class, and the colors for each entry identify the skipper. As highlited below, there’s a set of tabs at the very bottom of the sheet that allow a user to switch to different pages in order to view individual race line results, raw entry data, or summary sheets.

Sailors can even edit the various spreadsheet pages. If you make a mistake filling out the entry form, you can go to the Lap data page, find the error there and correct it. If any Hotlaps user wants to rearrange or sort the data for a particular page, please feel free to open a new tab on the spreadsheet to do that. You can then copy the data you’re interested in to your new page for editing, and leave the original intact.

plum gut feb24

click to enlarge

Of course Plum Gut is just one of the six Hotlaps venues. There are five more.

This collected lap data has many potential uses. Individual sailors can follow their own laptimes to see if different sailing strategies make a measurable difference in their scores, or they can compare how their times match up against other sailors in the fleet.

The hotlaps data also makes it possible to “performance handicap” the many, popular boats in SLSailing. As I’ve discussed before, that’s done by comparing the average lap time for a given boat on a particular racecourse against the same information for a standard, “index” boat: The Melges-24. After nearly two months of data collection, the Melges is looking like a great index, for a dozen reasons I wont bore you about here. If you own a Quest Melges-24, you likely know the reasons already. :-)

Anyway, here’s the handicap table as of yesterday. Below, the table to the left shows the handicap factors for boats on each of the six hotlaps courses (where the data is available). The table on the right shows the average handicap score for each of those boats, with the associated standard deviation for the small sample of values in each case.

summary tables feb25


So, how useful and reliable are the handicap factors?

Well, that’s what were still trying to figure out, but let me briefly talk about three points that came up in last Thursday’s Midnight Madness races.

hepurn feb21

Midnight Madness is a fun, multiclass race every Thursday at 9:00 pm, cosponsored by Danshire and Eden Bay Yacht Clubs. At the moment I’m using  Madness results to calculate potential handicap ‘adjustments’ and comparing them to the uncorrected, “normal” finish times.

As usual, a small but really great group of skippers showed up this past Thursday to race the Hepurn Hotlaps course. Here’s the result for race one.

Race One Lap Times: 
 Chaos Mandelbrot   M24 crewed — Start: 00:05  –  Last lap: 00:10:32
 Kris Hollysharp   M24 — Start: 00:01  –  Last lap: 00:11:18
 SteveLL Resident   Q2M — Start: 00:11  –  Last lap: 00:15:01
 qwerty Qork   IDQQ99 — Start: 00:02  –  Last lap: not finished
 Glorfindel Arrow   IDA81  – Start: 00:06  –  Last lap: not finished
Race One Results:
 1: Chaos Mandelbrot  (M24 crewed, 1.10) — 10:37 – corrected 11:40
 2: Kris Hollysharp   (M24, 1.00) – 11:19 – corrected 11:19
 3: SteveLL Resident   (2M, 0.76) — 15:12 – corrected 11:36
 4: qwerty Qork   IDQQ99 — not Finished
 5: Glorfindel Arrow   (M24, 1.0)  — not Finished
Unfortunately, qwerty and Glorf both crashed. Chaos and Kris both sailed Melges-24, and SteveLL sailed a Q2M.
R1 start
Kris was aggressive, extremely adept, and crossed the start line 4 seconds ahead of Chaos and Jane. However, a crewed Melges-24 can sail faster than one with a solo skipper, so Chaos was able to pull even with Kris and eventually pass her about midway through the course. Chaos went on to finish first, with an 18 sec. lead over Kris.
Looking at the prior handicaps however, a crew member gives an M-24 a roughly 10% performance advantage. Chaos’ corrected lap time would then be 11:40, a full minute behind Kris!
A similar issue came up with SteveLL. He was sailing a Quest 2-M, which is a much slower boat than the Melges-24. Steve cross the finish line a full 4 min. behind the lead boats, and there’s really no chance he could win a race without handicap adjustments.
However, factoring in the current handicap for the Q2-M (0.76) Steve’s corrected finish time becomes 11:36, a score that’s directly competitive with the two Melges in the race. In fact, with corrected scores Steve nosed out Chaos for Second Place!
second race finish
For the Second Race, a wondrous thing happened. There was a bright light from above, the heavens opened up, and Pensive Mission appeared at the race line, holding on to his Tako. pm and cmAlthough Pensive only makes rare appearances in regattas these days, he was one of Mowry Bay’s original Mow-Mows, and his skill with a Tako is part of SL’s nautical lore.
Well, in the Second Race we got a chance to see that legendary Boatman of the Mowry Apocalypse ride his Tako around Hepurn’s waters once more.
The Tako is quite a speedy boat and it’s powered by a real wind engine that makes beating to windward less of a hassle than most new boats. Thanks to Slanty Uriza, we also have a handicap from the Sulu Hotlaps Course. It’s 1.03, a close match for the Melges-24, so it made sense that Pensive was able to keep in close lockstep with both Chaos and Kris as the boats zoomed around the course.
A pleasant surprise occurred at the end of the race however, as I tallied up the scores. Since the Tako uses a very different wind engine, I wasn’t sure how “portable” the handicap factors might be within a mixed fleet or across different race courses. Well, to get a partial answer to that question I used Pensive’s single lap score to calculate a new Tako handicap for the Hepurn line.
Pensive’s Hepurn handicap worked out to 1.03, an exact match for Slanty’s Tako handicap using the Sulu line!! :-)
 It looks like the handicap factors are proving to be both valid and consistent. That’s a nice thing. :-)
Race Two Lap Times:
 Chaos Mandelbrot   IDCM91 — Start: 0:03  –  Last lap: 10:05
 Kris Hollysharp   IDKH47 — Start: 0:03  –  Last lap: 10:36
 Pensive Mission   ID25  – Start: 0:02  –  Last lap: 10:47
 Glorfindel Arrow   IDA81  – Start: 0:02  –  Last lap: 13:22
 SteveLL Resident   IDJB25 — Start: 0:05  –  Last lap: 14:40

Race Two Results:
1: Chaos Mandelbrot  M24 crew, 1.10 — 10:08 — Corrected 11:09
2: Kris Hollysharp   M24, 1.0 – 10:39 – Corrected 10:39
3: Pensive Mission   Tako 3.3 (1.03)  – 10:49 – Corrected 11:08
4: Glorfindel Arrow   M24, 1.0  — 13:24 – Corrected 13:24
5: SteveLL Resident   IDJB25 — 00:14:45 – Corrected 11:14

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Posted in announcement, Danshire Yacht Club, Eden Yacht and Boat Club, Flying Tako 3.3, Melges 24, Mowry Bay, Mowry Bay Boat Club, PHRF, Quest 2-M

Adjustment Bureau

Posted on February 16, 2013 by | 2 Comments

Mixed numbers

On February 14 a handful of hardy sailors converged on North Sea’s Breadnut raceline for a fun, mixed fleet race. We did two heats on the North Sea Hotlaps course, and everyone sailed a different boat class. Since the sim conditions were pretty good,  I thought it might be interesting to look at the results using the Handicap factors. Handicapping might “level the playing field,” and allow different boats to fairly compete with each other.

Feb14 mixed fleet

Here are the lap times for the five boats in the first race:
Race One Lap Times: 
Chaos Mandelbrot   IDCM91 — Start: 00:00:16  –  Last lap: 00:11:54
Melges-24 Handicap= 1.00
 takabou Destiny   ID0021 — Start: 00:01:48  –  Last lap: 00:12:15
Q IACC Handicap=0.92 
 Brett Kjeller   ID157 — Start: 00:00:27  –  Last lap: 00:15:19 –
RM12 new Handicap 0.75
 SteveLL Resident   IDJB25 — Start: 00:01:09  –  Last lap: 00:15:15
Q 2M handicap 0.77
 lesbo Charisma   ID159 — Start: 00:01:45  –  Last lap: 00:16:18
FranJac handicap 0.75
feb 16 handicaps
For each boat above I’ve also listed the handicap correction factor in red, based on the Hotlaps data for the Breadnut raceline, where available. Click on the figure to the right to get the current Handicap Summary Table, based on 269 laps sailed by 50 skippers in 32 different boat classes.
For each of the five boats in the race, I then corrected the Finish time by multiplying the boat’s lap time by the Handicap factor, then adding that result to the Start time. (I didn’t think it made sense to handicap the Start times). Anyway, here’s the actual Finish rank, with the corrected times shown in red.
Race Results:
 1: Chaos Mandelbrot   Melges-24 — 00:12:10 corrected: 00:12:10
 2: takabou Destiny   Q IACC — 00:14:03 corrected: 13:06
 3: Brett Kjeller   RM 12 — 00:15:46 corrected: 11:56
 4: SteveLL Resident   Q 2M — 00:16:24 corrected 13:20
 5: lesbo Charisma   FranJac — 00:18:03 corrected: 13:58
Chaos Mandelbrot crossed the Finish line first, sailing a Melges-24. The M-24 is the “Handicap Index” boat, so it needs no correction. Takabou Destiny crossed second in a Q IACC, which is 0.92 as fast as the M-24; adjusting for that handicap took 57 sec off Tak’s Finish time. Chaos still beat takabou, but only because Chaos crossed the Start line first; Tak actually sailed the faster time-corrected lap. :-)
takabou
Lesbo Charisma sailed a Francois Jacques and crossed the Finish in the #5 slot. Lesbo in FranJacThe FranJac is a great boat, but it’s considerably slower than the Melges-24.
Lesbo’s uncorrected time was six minutes behind Chaos. However if you adjust for the handicap (.75) her time is 13:58. Like takabou, Lesbo was late getting started; her corrected lap time was 12:13, a number that is suddenly competitive with Chaos’ 11:38 and tak’s 11:18 handicapped lap times. :-)
SteveLL Resident sailed a Quest 2M and ranked #4 crossing the Finish. There was no handicap available for the Q2M on the Breadnut line, so I used the Plum Gut Q2M handicap of 0.77. 
SteveLL
From past Hotlaps series, I’m pretty convinced the results from one standard course can be applied to most other courses.
You want proof of that (grin)? SteveLL sailed both race heats on July 14. Since we were racing the North Sea Hotlaps Course and using the Hotlaps wind, I took Steve’s race laps and used them to calculate a new Q2M handicap for the Breadnut line. It came in at 0.77, exactly matching the Plum Gut result! :-) SteveLL’s corrected Finish time was therefore  13:20, entrenching him in the #4 slot for the first heat. :-)
Brett Kjeller raced a shiny, new RM12 and Finished #3. There are no data for that boat on any of the Hotlap racelines. Brett’s laps can be used to set a new Handicap for the RM 12, but those numbers really can’t be used to adjust his own time in the same race.  :-)
However, it’s worth commenting that Brett’s lap scores from this race would yield a first-guess handicap of 0.75; if that number’s confirmed by more hotlaps, it would compare favorably with the FranJac (0.75) and Q2M (o.77) that were also part of this small, mixed fleet.
Brett
Here are the the results for the second race, again with handicap corrections added in red. I think the idea to handicap mixed fleet races is interesting, and there are probably several ways to do it. Using the hotlaps numbers is one method that might turn out valid and reliable over time.
Another method might be to simply group together boats that have a similar Handicap score; races often treat the VO-70 and OD-65 as though they were equivalent; the same is true for the ACA33 3.x and the Quest IACC,  as well as the Trudeau One, FranJac, and New York 30. Whether these boats can fairly compete with each other in a race is a question that might be answered, at least in part, by the Hotlaps project.
For the moment, it’s just fun to play with the numbers, and recall such great racing with friends. :-)
Race Two Lap Times:
 Chaos Mandelbrot   IDCM91 — Start: 00:00:11  –  Last lap: 00:11:40
 takabou Destiny   ID0021 — Start: 00:00:50  –  Last lap: 00:13:15
 SteveLL Resident   IDJB25 — Start: 00:00:26  –  Last lap: 00:14:59
 Brett Kjeller   ID157 — Start: 00:00:26  –  Last lap: 00:15:32
 lesbo Charisma   ID2159 — Start: 00:00:38  –  Last lap: not finished
Race Two Results:
 1: Chaos Mandelbrot   Melges-24 — 00:11:51 corrected:00:11:51
 2: takabou Destiny   Q IACC — 00:14:05 corrected 13:03
 3: SteveLL Resident   Q 2M — 00:15:25 corrected 12:24
 4: Brett Kjeller   RM12 — 00:15:58 corrected 12:05
 5: lesbo Charisma   FranJac — not Finished
mixed nuts

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Posted in announcement, Handicap Hotlaps, North Sea, North Sea, PHRF

Hot Times

Posted on February 6, 2013 by | Leave a comment

Hot Times Jan 2013

Thank you to all the skippers who have sailed Hotlaps so far. After five weeks in 2013, that adds up to 41 sailors doing 226 laps in 28 boat classes!

In the tradition of hotlaps from past years, I thought it might be fun to publish an ongoing list of the fastest skippers for the preceding month. To do that, I’m only considering boat classes that have lap times from at least three skippers. The lap times can be from any of the six different hotlaps courses.

I then normalize the scores from the different courses relative to the Melges-24 index. That makes the results comparable, and independent of the specific race line a sailor chooses. Based on that comparison, here’s a list of the speediest hotlap skippers for the month of January!

Hot Times Table Jan 2013

For example, during January sailors posted a total of 49 lap times for the Melges- 24. For each of the courses it’s possible to calculate the average lap time for that boat, and then determine the skipper that beats that average by the widest margin.

In January, Armano Xaris and Fearless Freenote ended up in a tie. They each sailed a Melges-24 lap that was 9.0% faster than the average for the fleet. Nice sailing, guys! :-)

Kudos also go to  nozumimi karu, xpaul pain, Hannelore Ballinger, Bunnie Mills, Jane Fossett (that’s me!), Lucyinthesky Aferensis, and VictorCr for the fastest laps in their respective boat classes, as listed above. Nice job!

Now let’s see how the scores in February measure up over the next few weeks, but please remember: Hotlaps isn’t just about the fastest scores; be sure to enter your ‘good, average’ laptimes as well!

HL2013

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Posted in announcement, Handicap Hotlaps, Melges 24, PHRF, Racing, Sailing Skills

Two Hundred Hotlaps

Posted on January 28, 2013 by | 2 Comments

200 hotlaps

This post is just a quick update and reminder about Hotlaps. :-)

Hotlaps 2013 is a format that lets sailors build sailing skills and have fun by doing solo practice runs and sharing the scores online. The database allows skippers to compare their lap times with others; they can also contrast the relative performance of different boats sailing the same ‘trial lap’ conditions.

At the moment, there are six different raceline locations, and each has its own Hotlaps course: PLUMGUT, BREADNUT, KNAPTRACKICON, LINKOUS, SULU, and HEPURN.

hotlapsposters

Sailing a Hotlap takes only ten minutes, and you can do it any time you want, in any boat. Just go to one of the racelines and click on the ‘Hotlaps 2013′ poster above the green buoy; it will give you all the info you need.

The current round of Hotlaps began less than four weeks ago, and yesterday we hit a total of 200 lap entries recorded by 36 skippers in 26 different boat classes. Notohama Resident has the notable distinction of sailing lap #200 in a Flying Fizz at Plum Gut. :-)

Speaking of which, please let me give a shout-out to all the sailors who have sailed laps so far this month. Woots! :

 yala74, Armano Xaris, Jane Fossett, Andi Merryman, Lance Corrimal, LucyInTheSky Afarensis, S11D, Emelia Azemus, B117, B12, BM12, Chaos Mandelbrot, Hay Ah, Kris Hollysharp, Slanty, poko Zepp, Qyv Inshan, Justin Blade, nozomimi karu, SkyBlue Earthboy, Trapez Breen, Yuukie Onmura, Joy Acker, Wolfhard Resident, notohama Resident, Pazzo Pestana, Kentrock Mesmer, Bunnie, , VictorCR, B112, Maiko Taurog, xpaulx pain, Fearless Freenote, Rim Telling, Xi Larnia, Hannelore Ballinger.

Here’s also a new update for the Plum Gut spreadsheet that I posted ten days ago, so you can get an idea where this is going. Please click on the image below to get a readable size, and you’ll see it includes all the individual Plum Gut Hotlaps scores, color- matched to the skippers. The online spreadsheet has separate pages for each of the racelines. It makes it easy for a sailor to watch their progress over time, and to compare their skill against others running the course.

Hay Ah’s currently testing out an interactive display that should soon make this Hotlaps info much more user-friendly and available to skippers in-world, right at the raceline. :-) (Thank You, Hay!)

Plum Gut Hotlaps Jan28 2013

please click to enlarge

The Hotlaps data makes it possible to generate simple performance handicaps for different sailboat classes. The handicaps are normalized with respect to an index boat (the Melges-24 has a handicap of 1.00) to make the handicaps factors easy-to-use.

So far, across the six different courses a total of 26 boats have been evaluated, yielding 64 estimated handicaps. Here’s the current list for all six courses:

HH Summary Jan 27

At the end of this month I’ll post about the conclusions we migfht be able to draw from this type of data, and I’ll also list the names of skippers who logged the fastest adjusted lap times for each boat class during January. :-)

However, if you sail hotlaps please remember to log all your “average, good” lap times, not just your fastest runs. That way we’ll get a more realistic profile for each of the boats in the fleet.

overlapped and parallel

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Posted in Handicap Hotlaps, PHRF

Hotlaps 2013 Progress

Posted on January 9, 2013 by | 5 Comments

HH jan 2013 header

The Hotlaps 2013 lap entries are growing; in the first nine days, seventeen skippers logged a total of eighty-six laps that are split across the four courses.

jan 8 sailors HH The skipper’s names are listed in the box to the right, and the colors match the time-trial entries that are included on the summary spreadsheets for each Hotlaps course.

Plum Gut has the largest number of laps so far, with fifty-three lap times logged for fifteen different boats (see below).

The Melges-24 is the tentative “Index Boat” for handicap comparisons, so it deserves special comment here. The average Plum Gut lap time is 8:46, based on seven runs by Armano, Yala74, and Kris. Although the number of entries is still small, the scores are consistent and tightly grouped with a standard deviation of only 10 sec. We’ll see if this changes as more laps get added, but so far the M-24 Index looks valid and reliable. Let’s see if that holds up as sailors add more data points.

Jan8 hh

Please click to enlarge

Below is a quick ‘Summary Table’ of Handicaps for the fifteen boat classes entered so far.

HH Summary Jan8 2012Knaptrackicon still needs Index laps, so it’s handicap factors are blank at the moment. However, where the data is available, the scores of the other three lines are pretty consistent. The WildWind boats are by far the speediest, with Wildcat45, RCJ-44, and TR30 all earning handicaps of 1.10-1.15 (meaning they are 10-15% faster than M-24). In contrast, the newly reworked JG-44 looks like it’s coming in with lap times that are roughly 15% slower than M-24 on all three courses. The Mesh Shop boats and the ACA33v3 look like they fall in the middle, while the Trudeau fleet, Caf Binder’s Jangars, Manul Rotaru’s BeachTri, and Balduin Aabye’s Bolero all come in at the back of the pack with scores 30 – 40% slower than the Melges.

Of course, a slow boat is not a “bad” boat. Several builders argue that slower boats are more realistic in SL waters, but that’s a discussion for another time. :-) The point here is that the handicaps are generating meaningful data, and we’re on track to fill in many of the blank spaces on the above form. :-)

Yesterday I sent out posters to advertise Hotlaps. They are full mod/copy, so please stick one up in an appropriate place (like your local gas station bathroom). The notecard embedded in the poster gives details about Hotlaps 2013, including landmarks, charts, and links. The notecard is networked, so the Info will automatically update as we add more Hotlaps locations, and as Hay Ah adds new lap features to her racelines.

Hotlaps 2013 info

You got ten minutes?
You could sail a Hotlap! :-)

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Posted in Danshire Yacht Club, Fishers Island Yacht Club, Fruit Islands, Handicap Hotlaps, Melges 24, PHRF, Second Life Sailing, Zindra

PHRF Numbers: A Classy Standard, With More Wild Boats!

Posted on April 20, 2010 by | 2 Comments

 

Note: If you are a new sailor on the digital grid, let me apologize for the short article below.
It’s full of jargon, statistical terms, and obscure references.
Good Grief, it reads like a work memo!
Second Life Sailing’s PHRF is actually a lot of fun; it’s based on an old SL Sailing Hotlaps’ idea started by three very ‘real’ sailors: Cory Copeland, Cybrid Keats, and Kanker Greenacre (all smart skippers and all very funny people).
So…. if you are new to Hotlaps and PHRF, please don’t read this article!!  Instead, go read an Intro here.
You can then find a massive bibliography of links and posts on the history and updates to the SL-PHRF thing at the end of a recent article located here.
Actually that sounds too tedious… If any of that stuff in those articles sounds like you, please then come back here.
And if you’re a RL sailor and you don’t find what you’re looking for… no problems!
SL Sailing is a nice emulation of the real thing, and we have a global community waiting to cruise, race, or script the limits of your imagination…
If you have a question, just post a comment and ask! :-)

 Last week I talked about  SL-PHRF numbers and posted a table of PHRF ”handicaps” for a fairly large number of boats using the 2009 Madaket course. We switched to the “PHRF 2010 Course” on January 3rd, but I couldn’t report on those numbers at that time, since I thought it was important to change the “PHRF index standard.’ Based on the 2009 data, I thought the J-Class was the obvious choice as an Index Boat.

The ‘Index’ is the boat used for comparison; it’s a bit like like ’par‘ in golf. The J-Class ‘average, good’ lap time on the 2010 test course arbitrarily gets a handicap of ’1.00,’ and all the other boats are assigned handicap conversions relative to that number.  A boat with a handicap of “1.13” is thirteen percent faster than  the Index boat , and a boat with a handicap of  ‘0.74′  is 26% slower.  The handicap conversion factors make it easy to level the playing field across a mixed fleet, at least with regard to solo lap times over the past few weeks. 

I commented last time that I needed 8-10 new J-Class data points to strengthen the ‘index’ for PHRF comparisons on the 2010 Course. Huge kudos to Trapez Breen and Chaos Mandelbrot for racking up thirteen new laps that fall right in a normally-distributed range, setting a basis for a new index. Norway and Texas fell dead-on the same statistical curve, volcano or not blocking their flight path! :-)

Let me take a few sentences to comment on the choice of a new ‘index standard’ on the new test track.  The 2010 PHRF Course is roughly two sims longer than the 2009 course and in my opinion it is a better test track.
I guessed it would be perhaps 10% longer for most boats, given the extra distance and the  headings. Trapez and Chaos’ scores  came in a bit better! The new J-Class Lap time is 9.2% longer than 2009! Wow, the individual lap times and the time shift onto the new, longer course were close enough to endorse the J-Class as a new PHRF standard.  As we add more skippers and more data points in the next few months of course the baseline standard may shift appropriately; but this is a great start, with remarkably tight lap time- concurrence.

OK!!! In the first chart below, I repeat the 2009 scores through January 2, 2010. It shows the average lap times for the 2009 Madaket course, as well as the ‘corrected’ handicaps for all the boats sailed. Where available, the 2008 column shows earlier handicap data for a  large number of boats on several other test courses. There is pretty remarkable correlation over time and across multiple test scenarios.

Woots! OK the above table is closed, ended; it’s a dead-parrot.

We’re now switching to the 2010 course in an effort to demonstrate construct validity and reliability (we’ve done this as half-dozen times before). On the new course so far we have the Index boat scores, but we also have a total of 58 new test laps sailed on a variety of other boats!

Let me give a huge shout-out to Wally Warbaum, Colin Nemeth, Glorfindel Arrow, Francois Jacques, Lance Corrimal, Fearless Freenote, Trapez Breen, Aislinn Farella, Allie Tomsen, TaffyOcean Sommerstein, Slanty Uriza, Kembri Tomsen, Pensive Mission, Armano Xaris, Jane Fossett, Chaos Mandelbrot, Vin Mariani, and ahjep Kattun for running so many laps on the new 2010 course in a wide variety of boats.

WOOTS!!!

At the moment I’m only reporting on a few boats; I’m waiting for the rest of the entries to reach statistical significance. However, if you are geeky enough, the numbers so far look pretty interesting! Although there are a few thousand  entries in the current database, there are only 58 valid laps on the current test course;  it will take several months to demonstrate the current results are consistent. 

Since we are changing the Index, for me the biggest question is whether the 2010 results correlate with the all the prior 2008-2009 lap info; actually, so far it looks pretty good!
For example, the  ACA33 v2.53 ranks a fast handicap score of 1.33, much faster than a J-Class but still slower than a Tako. That’s consistent with earlier ACA scores.

Even more accurate, the  WildWind RCJ-44 demonstrates an average lap time of 10:12, meriting a  handicap of 1.33; that’s a full 33% faster than a J-Class on the same course. More importantly, on the 2009 course the RCJ-44  earned a nearly identical ranking of 1.32, evidence the scores are valid and reliable year-to-year.

Given that very tight WildWind result, let me give a huge shout out to Orca Flotta and the entire sail team over at Triumphal; Woots!!!
They’ve logged a flood of new WildWind scores on the test track, adding several new boats to the list! Welcome to the SC22, SC 27, and SC35 v2.0!!!
And although there’s only one lap entry, let me send a shout out to Lance Corimmal for adding the TR-30!!!

Lots more to come soon!!!

 

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Posted in J-Class, PHRF, Racing, Sailboats, Sailing Skills, Wildwind

PHRF Update for 2009

Posted on April 12, 2010 by | 1 Comment

On April 9, 2010, Chaos Mandelbrot posted:

April 9, 2010, J-class. This was my first time on the 2010 PHRF course with the J. Sim conditions were poor. Fractal came to a dead stop 3 times. Twice due to sim conditions. The third time was hitting a shoal just W of Indian rock. This course does not show off the J-class speed. The reaches are not at the optimal J-class angle. I suspect much slower boat speeds on this course than the previous PHRF course.

Thank you for your comment, Chaos! It’s about time I updated PHRF stuff!

In case anyone is unfamiliar with it, the PHRF Handicap project collects solo lap data from skippers who sail a simple, classic ‘test course.’ The results are automatically uploaded to a web database, and the data is then statistically filtered and pooled to determine an ‘average, good’  lap time for each class of boat under under the test, fixed conditions. It’s easy and it’s fun, and any skipper can try it out any time they want, in any boat they choose. Since everything is always the same, sailors can use the Madaket course to sharpen their skills, try new things out, and document the changes over time.

The pooled information over the past 26 months involved nearly a hundred individual skippers who sailed several dozen boat classes on eight different race courses. Ocean Racers (click to enlarge)Those efforts generated a few thousand ‘valid lap score’ entries. That robust database makes it possible to calculate ongoing valid and reliable ‘handicap factors’ that compare  the average performance of different boats that sail in SL. I posted the most recent handicap update in November 2009; that post includes a bibliography of many prior articles that discuss the handicap system, and should answer just about any question.

For most of 2009, the PHRF course started in Madaket and followed a route that included equally-sized beat, run, and reach legs, using the buoys in Cannonade and Flotsom as marks (see the charts below). On January 3, 2010 however, the Cannonade yellow mark moved to Howser; that forced an official close to the 2009 PHRF test course. Actually, that was no big deal, given the large amount of data already collected; it was time for a new course anyway!

The new “PHRF Hotlaps 2010″ course uses the rock in north-central Indian sim as the upwind mark; it stretches the upwind/downind leg an extra twenty percent or so. It also does something a lot more important; if you look at the 2009 course below, it has two “Reach” legs from the yellow mark to green, and then back again. Those two tacks on the 2009 chart are beam reaches, and they only test performance on a single  boat heading. M1sha Dallin pointed this out many months ago, and I think she’s right, the course could be better.

The new ’2010′ course shown below fixes this problem, at least to a small degree. The angle between Indian Island and the Green Mark turn those legs into a close reach and a broad reach, and hence make the course — potentially — a better test track. Having said that, I must admit that every course we tried over the past two years produced near-identical performance rankings, evidence that the results are valid, reliable, and ‘portable’ to other courses.

2009 and 2010 Madaket PHRF Courses

Chaos stated above: “This course does not show off the J-class speed. The reaches are not at the optimal J-class angle. I suspect much slower boat speeds on this course than the previous PHRF course.”  I admit that Chaos may well be correct, the new ’2010′ course might not be ideal for J-Classic.  In fact, I hope it’s not; that’s not the intention.  The PHRF course is just intended as a simple, quick, and ‘fair’ test of  a boat’s basic sailing performance. It shouldn’t be tuned to the advantage of any particular boat.

Having said that, let me get back on topic here and post the ‘final’ update on PHRF scores for the 2009 course; the summary table below includes handicap adjustments based on all valid laps sailed prior to the switch on January 3, 2010:

The left column lists the name of the boat, and the second column lists that boat’s ’average good lap time’  for the 2009 PHRF course shown above. To generate a simple performance handicap score, two years ago we chose the ‘Trucordia Yawl’ as an index boat, since it was popular and its lap speed was in the middle of the pack. A given boat’s ‘handicap’ was defined as a simple ratio: [Yawl Average Good Lap Time] divided by [Test Boat Average Good Lap Time]. That ratio repeatedly demonstrated that a boat like the Tako was 30-35% faster than the index Yawl, while the Trudeau Tradewind proved 47-55% slower. The 2009 handicaps are listed in blue in the third column, and the fourth column shows the 2008 handicaps, where available.

 The latest summary numbers above don’t show any new surprises. That should be reassuring, and actually pretty consistent with sailors’ predictions. For example, I commented many weeks ago that the Trudeau Columbia handled much like a J-Class, with a few extra features thrown in.  The latest numbers reveal a J-Class handicap of 1.00, while Columbia scores a 0.99.   I’d say that was pretty close!

I think I’ll stop commenting there however, because I still have a few months’ worth of  numbers to look at, based on the new ‘Hotlaps 2010′ race course. But before I can post those scores, I think it’s important to change the index boat!

As I mentioned above, for two years I’ve been comparing everything to a Trucordia Yawl. That boat uses a Real Wind engine, similar to the original Tako. It was highly appropriate many months ago, but these days most boats (including all modern Trudeaus) use Apparent Wind algorithms to power the sails. I think it makes sense to switch to an index boat that uses Apparent Wind.

I originally thought to use the Trudeau Twenty or even the Knockabout as an Index. However, after looking at the most recent numbers, I changed my mind. There are seventy-seven J-Class data laps for the 2009 course, and the J-Class Handicap ended up a perfect “1.00.”

 However, I can’t recalculate the last three month’s data on the new Madaket 2010 Hotlaps course until I get more J-Class lap scores. As soon as I get a few more laps from different people (I need a total of maybe only ten more), the rest of the numbers should fall in place and I can post another updated table incorporating the modern index.

How geeky is that? :-)

 

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Posted in PHRF, Sailing Skills

November PHRF Update

Posted on November 20, 2009 by | 3 Comments

PHRF  handicaps
Here’s a quick update of the  PHRF Handicaps, including new boats and stronger numbers. “Handicap Hotlaps” is a fun way to test your skill against other sailors on a short, test-track solo race course. If sailors think they ran an ‘average, good lap’ on the PHRF course in current use, they can save their scores in a database for future reference, and that data will also be used to set ‘performance handicaps’ for different sailboats in SL. The laps are fun, quick and build sailing skills… and after two years of databasing the results, I admit the finding are also pretty interesting.

I posted a summary of PHRF handicap results a few months ago. Since then, many sailors have continued to add laps and try out new boats using the Madaket web-liked PHRF database that is the current PHRF test track. I’m still going through all that information and doublechecking it with boatwrights and beta-testers, but at the request of several sailors let me give you a quick snapshot of a few new boat scores and adjusted handicaps. My hope is to update the  summary handicap information here at least once a month from now on, since the J-CLASSIC Regatta that was taking all my time is now safely tucked away in hiberation!

First off: Let me give another huge thanks to Cynthia Centaur and Francois Jacques for all their assistance developing and expanding the ”PHRF Handicap” idea, and helping set up the current test line in Madaket. Oliphant Ming and Chaos Mandelbrot were also invaluable problem solving issues and discussing features.

But let me give the biggest woot out to all the skippers who ran laps and contributed their scores!

Gemma Vuckovic, Francois Jacques, Carmen Foden, joro Aya, Garrick Diesel, Justbent Clarity, Heidi Stiglitz, Angus Moonwall, Dunan Wilder, Chaos Mandelbrot, Cory Copeland, LDeWell Hawker, Oliphant Ming, Julia Ceres, Liv Leigh, Triton Sands, Hal Burnstein, Blackbird Latte, Argus Farman, Vin Mariani, Rodman Mapholisto, Alain Gloster, Jane Fossett, nobuko Criss, Allie Tomsen, Angus Moonwall, Bunnie Mills, CS Price, Emme Eales, Jehan Jameson, Liv Leigh, Naeve Rossini, Nomad Zamani, Reven Fhang, Quirky Torok, Isis Rexie, Everest Piek, Arrekusu Muromachi and Masahisa Greenwood, Herris Merlin, disisme Misfit, Armano Xaris, Charlz Price, Deserted Rhode, Axle Wharton, Dutch Hoorenbeck, Pensive Mission.

Here’s the new table, but please note there are many new boats and laps, and this is only a partial update; I’ll add the rest soon. The table below follows the same format and conventions as  previous ones.

Since the last update a few months ago, sailors have  contributed lap data for several additional , popular boats.

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Posted in PHRF

PHRF Handicaps, Wild Winds

Posted on August 11, 2009 by | 17 Comments

phrf handicaps july 19 2009

PHRF  handicaps
Here we go! The most recent PHRF Handicaps, including a few new boats, and some tighter numbers!

In the last few weeks, despite some pretty terrible grid-crossing conditions, a group of stalwart skippers added more hotlaps scores to the PHRF database. Thanks to:

Gemma Vuckovic, Francois Jacques, Carmen Foden, joro Aya, Garrick Diesel, Justbent Clarity, Heidi Stiglitz, Angus Moonwall, Dunan Wilder, Chaos Mandelbrot, Cory Copeland, LDeWell Hawker, Oliphant Ming, Julia Ceres, Liv Leigh, Triton Sands, Hal Burnstein, Blackbird Latte, Argus Farman, Vin Mariani, Rodman Mapholisto, Alain Gloster, Jane Fossett, nobuko Criss, Allie Tomsen, Angus Moonwall, Bunnie Mills, CS Price, Emme Eales, Jehan Jameson, Liv Leigh, Naeve Rossini, Nomad Zamani, Reven Fhang, Quirky Torok, Isis Rexie, Everest Piek, Arrekusu Muromachi and Masahisa Greenwood.

Here’s the new table, and it follows the same format and conventions as  previous ones. (Note: I updated the tables below on August 12 based on Lance’s suggestion to post alphabetical and performance-sorted versions. Bosth are shown below. I’ve also color-coded the boat names, based on the wind engine.)

phrf-july-19-2009-name

phrf-july-19-2009-hi-low copy

Compared to the last update in early June, the numbers are more consistent and seem to be falling in line with the results from 2008 PHRF (where available). Thanks to Live Leigh, we’ve added a new boat too, the Catfish 33 catamaran. We need to get numbers from other skippers on it, but my guess is Liv’s PHRF lap probably hit it on the nose for this boat: Her lap came in with a perfect, corrected Handicap score of of 1.00 for the new fishy cat!

The JMO-60 is also new on the PHRF list, coming in with an average Madaket lap time of 8:55 and an adjusted handicap of 1.32. This makes the JMO-60 comparable racing to the RCJ-44, as predicted by the very similar polar plot results for the two boats. All three WildWind boats so far tested (RCJ-44, JMO-60, and VOJ-70) prove extremely fast, particularly compared to other boats powered by ‘apparent wind’ tested at Madaket (such as the Shelly, Catfish, and Trudeau Twenty family).

The Wildwind’s strong showing on lap testing appears to be partly due to the way it handles Apparent Wind.

Wind power.
There are three different kinds of wind most sailors think about, whether they sail in Real Life or in Second Life.

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Posted in PHRF, Racing

Smart Boat Madaket HUD

Posted on July 3, 2009 by | 2 Comments

tom247 woodgett_026a

Navigating across multi-sim waterways is a common problem, particularly for a new sailor trying to learn a race course. Most sailors refer to race charts and keep a Mini-map open on their screen to monitor their location. That really doesn’t work too well in Blake Sea, however, since there are many submerged objects that clutter up the mini map, making it pretty useless. It’s also very difficult to see Blake race buoys on the World Map!

 In response to sailors’ frequent complaints about this, Chaos Mandelbrot and Joepie Korobase both put together simple HUDs that help sailors identify specific landmarks, such as race buoys. Although these HUDs work quite nicely and many people like them, I never found them very helpful. Any additional gadgets I need to adjust or keep track of during a race just seem to make things more confusing.

For the past few weeks, however, I’ve been using a GREAT, very simple HUD made by Tom247 Woodgett. It does exactly what I want, and it’s so simple to use even I don’t get confused. I think this HUD could be great for teaching, and Tom247′s agreed to offer sailors a version for Blake Sea that shows the Madaket PHRF racecourse for just $1L!

Tom247 hud 01

 The HUD sits in the corner of your screen and shows a tiny image of the Madaket PHRF Racechart. You can see it in the picture at the top of this article. If you click once on that HUD icon it pops up to normal chart size, as shown above. Your boat’s location on the chart is identified by a red dot that’s continuously updated while you sail. With that one click you can instantly see where you are.

If you click the map again, it goes semi-transparent, so your view of other boats and markers won’t be obstructed. If you give it a third click, it goes ”poof” back to the corner of your screen. There is nothing to set up, no calculations, no buttons to mis-click.

Tom247 makes interactive charts for use with his powerboats so he’s an old hand at this. He’s offerring the Madaket Map HUD for $1L at his store in Firespire and at the NYC Loft. If people find it useful, he’ll offer a wider range of racemaps and options for sailors.

Give it a try, tell tom247 what you think. For $1L… you may never get lost in Blake Sea again!

NYC Loft

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Posted in Blake Sea, PHRF, Racing, Sailing Skills