Category Archives: Mowry Bay Boat Club

Hotlaps tops 300

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. ūüôā

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. ūüôā

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!! ūüôā
¬†It looks like the handicap factors are proving to be both valid and consistent. That’s a nice thing.¬†ūüôā
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

Hepurn Hotlaps

Hepurn Hotlaps

Kudos to Hannelore Ballinger, Elbag Gable and Mowry Bay Boat Club for hosting the sixth Hotlaps 2013 site!

The new course uses the Linden raceline in Hepurn, and you can get all the details to sail a Hotlap by clicking the poster above the green buoy on the starboard side of the line.

Mowry Bay Hepurn raceline

(Note: The posters are phantom and semi-transparent, so they aren’t an obstruction to sailing.)

There’s a large rez-enabled parcel on Linden water that begins 35m south of the raceline, so sailors should have no trouble getting their boats underway.¬†The Green buoy also contains Hay Ah’s version of the WWC setter, so if you want the correct wind to sail a lap just click on the buoy and say “use hotlaps 2013.”

Here’s Hanne’s chart:

Mowry Bay Boat Club Hotlaps 2013

The course is classically designed with upwind, downwind, and reach legs. It resembles the old MBYC1 “Triangle” course that sailors raced in the Mowry Sprints regatta (you can read about that race¬†here, here, and here). ¬†It’s interesting to note the old MBYC1 course was used for racing and hotlaps as far back as 2006-2007. However, by comparison Hanne’s new course is over twice as long, it takes better advantage of the Linden waterways, and it is a better test of basic boat performance. It’s a great design. ūüôā

There’s one unique aspect to this course compared to the other five Hotlaps installations. Hepurn Hotlaps uses a SW wind (15kn, 225deg), so the first leg of the course is a downwind run. Since Hotlaps are solo time trials and the legs are nicely balanced, I’m guessing the ‘spinnaker start’ in Hepurn will make no difference.¬†We’ll see!

So here we go with Hepurn, Now We Are Six!

Now We Are Six

Hotlaps Locations:

Plum Gut






(click one for a link.)


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

mowry mar5 2008