Facebook

Login

Support Sailonline

If you haven't already - join the SAILONLINE YACHT CLUB!

Please also consider making a donation - all amounts are greatly appreciated!

Board » General Discussion » IMSYC 2011

Page: 1 2 3 4 5 6 7 Next Last

Posted by
A2


Users avatar

Posts
347
Registered at
2009-10-26 00:39:42
2011-05-30 16:15:45 - IMSYC 2011
This event is one of my favorites here at SOL. Evaluating the design offerings by the emerging class of budding naval architects gives this race its unique distinction.

IMSYC-66 C.O.R.E. values

Methodology:

I have chosen to employ an Ordinal ranking system that is common to duplicate bridge competition where the results are compared to players holding identical cards with bidding and sequence of play the only variables.

This year the polar txt files provide data for 18 points of sail for each of 6 different wind speeds for a total of 108 data points. Within each data point a design is awarded 1 point for each design that it has a higher value than.

Therefore with 11 designers represented 10 is the maximum award available for any given element and 5 is the median.

Here for brevity's sake I will list only Upwind & Downwind composites utilizing TWAs of 90 and below for the former & 100 and higher for the latter.

Comparative Ordinal Ranking Evaluation

Boat . Upwind . Downwind

A: ___ 9.46 ___ 9.28
B: ___ 8.35 ___ 8.18
C: ___ 8.22 ___ 6.49
D: ___ 6.37 ___ 7.64
E: ___ 6.03 ___ 6.82
F: ___ 3.59 ___ 5.66
G: ___ 4.87 ___ 3.62
H: ___ 4.37 ___ 2.56
I: ___ 2.32 ___ 1.31
J: ___ 0.69 ___ 2.18
K: ___ 0.72 ___ 1.27

This years leading design obtained a Max performance value at 83 of the 108 data points in the array demonstrating unparalleled excellence across the board for upwind & downwind points of sail in medium to light wind conditions.

I have substituted letter codes for the boat designations so that others may conduct their own analysis without prejudice.

--- Last Edited by 8mR Who at 2011-05-30 17:02:00 ---
None so blind
Posted by
RainbowChaser


Users avatar

Posts
2656
Registered at
2009-06-14 09:44:50
2011-05-30 18:44:35 - Re: IMSYC 2011
Now if THIS post doesn't generate discussion about the IMSYC boat designs this year then nothing will!!! :-D

Thanks!!
Posted by
Rod


Users avatar

Posts
392
Registered at
2010-06-24 22:30:48
2011-05-30 22:21:24 - Re: IMSYC 2011
To 8mR Who
I have attempted to evaluate the 11 designs, but in a subjective way (not mathematical). I note also that two of the designs are clearly superior, but I also note that the maximum downwind performance occurs at different TWAs. Does your procedure account for performance characteristics of this kind?
I assume that someone will run a 'router' simulation in a number of different wind regimes and derive a more exacting evaluation---but it won't be me, and therefore I conclude that I have little chance of winning for my design choice----but I will sail my eventual choice---and hope for the best..
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
Posted by
A2


Users avatar

Posts
347
Registered at
2009-10-26 00:39:42
2011-05-30 23:17:49 - Re: IMSYC 2011
I have read the proposals provided by the link on the front page blog post of this site. The designers applied their VPP's to SailPlanner to estimate their optimized solutions.

Based solely on the published polar txt files provided by all the designs, the leading boat indicated by my list has the maximum value for 66 of the 72 points of sail for 8m/sec and below, conceding only 3 upwind TWAs to the 2nd place boat & 3 downwind TWAs to the 3rd place boat.

To be sure all I have done is rank the values not predict a winner nor choose a route. This procedure however does narrow the field for those who wish to do a more definitive analysis. That being said I believe the best strategy is a well developed polar, your mileage may vary.

--- Last Edited by 8mR Who at 2011-05-31 00:27:51 ---
None so blind
Posted by
76Trombones


Users avatar

Posts
362
Registered at
2009-08-03 18:04:56
2011-05-31 02:47:27 - Re: IMSYC 2011
This was a much trickier challenge than previous IMSYC, and I suspect that some of the students are glad to see the back of it! ;-)

Not only were the designers given free reign over pretty much every aspect of the hulls and rigs but they had to get them through a "slightly" finicky validation process (permission to throw crumpled up midterm exams at instructor). Oh, and write and debug a pretty solid VPP to boot!

I'm always curious to hear more about the design process - a couple of the reports stand out from this point of view.

I implemented Jakob and Mikael's code and spent a weekend monkeying with it. I did some "designing" but no optimising, which is usually much more work than fun...

My "traditional" hull was built to be a minimum displacement, max LWL, min beam, min depth, min CP with full width flare (convex) at bow and stern. You'd never do the last part in particular designing IRL, but this exercise is in some ways the opposite of what racing boat designers usually do. Sort of VPP equivalent of a winged keel.

Once the hull had been trialed I shifted the centres back a bit for a small boost. No limits imposed here, and probably a chance to exploit a loophole? Didn't investigate.

My hulls were parametric. I can't imagine trying to get a digitised lines drawing through the checks. Another alternative would be to use CAD - Free!ship or any other NA package will generate tables of offsets that convert easily to the britfair format use here.

Two rigs - a high aspect "wing" with no draggy headsails, and a one with spin. You pay full-time a weight penalty for the ability to carry a spin even with no jib set. Bummer :-)

The wing is faster through about TWA140-150. We'll have to make up VMG downwind by playing shifts. The trad rig is a better all-rounder maybe, but maybe less fun.

----

It's possible to built a "scow" hull with massive righting moment on a nice narrow immersed section. Tricky to pass the rules, and I had trouble keeping the VPP stable, but otherwise it's faster than the "monohull". There seems to be an unadvertised limit (hmm) that KG must be neg, which hurts this approach. I ended up carrying around unneeded lead.

----

Kudos to the design teams for their very hard work, and thanks to jakob for bringing this to SOL (or vice versa). Special thanks for sharing the course material. Better than a crossword! :-)

76T
Attachments
Posted by
sol


Users avatar

Posts
297
Registered at
2008-08-14 11:08:14
2011-05-31 08:08:50 - Re: IMSYC 2011
8mR would you go into a little more detail how you did this... i understand you ranked each boat on each TWA/TWS in the polar and then award 10 pnts to first, 9 to 2nd etc for each point, then what? Added them up for the upwind and downwind angles as you specified ?
And somehow normalised, how divide by 108? (or however many data points there were?)

Awesome idea, including this for vmg angles would be extremely helpful...

I take it you have a mac from your comment in 'Useful Free Tool' thread, so perhaps you may not be able to use this, atleast not without WINE or similar, but I posted a new tool over on soltools.wordpress.com that is particularly useful for this race ;-)

----------------

Who wrote this post please?



--- Last Edited by RainbowChaser at 2011-06-07 08:33:58 ---
Posted by
A2


Users avatar

Posts
347
Registered at
2009-10-26 00:39:42
2011-05-31 13:26:47 - Re: IMSYC 2011
I tried to explain my methodology but I am more than willing to dispel any lingering confusion.

This is a ranking of the boat speeds achieved at each TWA for each W.S. listed in the polar txt files. There are 18 points of sail for each of 6 wind speeds. So it is a straight forward spreadsheet table. I divided those data points into 2 groups of 9 each, 30~90 & 100~180.

If all the boat speeds are different, then you will do a sort and corresponding assign ordinal values of 10, 9, 8, 7, 6, 5, 4, 3, 2, 1 & 0 for those designs, at that data point.

In some cases there are equal boat speeds listed in which case 1 point is awarded for each design that is below that mark & 0.5 for each design that it is equal with, for example; 10, 9, 8, 7, 5.5, 5.5, 4, 3, 2, 0.5 & 0.5

In an array of 11 boats the total for these ordinals is always 55.

From there it is only just the basic average for the number TWAs for the given subset. All the upwind ordinals added together divided by 9 and likewise the downwind ordinals.

This is done for each Wind Speed and then similarly averaged together.

If not done in this fashion for simplicity's sake here in the forum, where formatting is not possible, there would be 108 separate categories, which is how the spreadsheet is organized prior to any averaging.

In effect all upwind ordinals added together divided by 54 and then the same for the downwind ordinals.

The numbers in the list represent the average ranking, not the boat speed.

While this approach may not be very sophisticated and lacks quantitative specificity, it clearly identifies those boats at either end of the performance spectrum.

--- Last Edited by 8mR Who at 2011-05-31 15:22:53 ---
None so blind
Posted by
captjack1942


Users avatar

Posts
239
Registered at
2008-01-18 03:24:03
2011-05-31 16:18:48 - Re: IMSYC 2011
Did you take into account prevailing winds in the Western Med and East Atlantic in June?

http://www.offshoreblue.com/navigation/pilot-charts.php
Posted by
A2


Users avatar

Posts
347
Registered at
2009-10-26 00:39:42
2011-05-31 16:45:07 - Re: IMSYC 2011
The boat designers took into account the expected wind conditions, I have merely taken their output and compared them to each other. In doing so I identified a particular boat that is faster on 66 out 72 points of sail for 8m/sec and below wind conditions.

Not only that but it out performs the other boats going up wind at the higher wind speeds as well. It does not have the reaching capability in higher winds of the 3rd & 4th place boats however, so if the weather gives you that option for the majority of the race then you would be well advised to pick one of those.

--- Last Edited by 8mR Who at 2011-05-31 16:58:59 ---
None so blind
Posted by
sol


Users avatar

Posts
297
Registered at
2008-08-14 11:08:14
2011-05-31 17:20:54 - Re: IMSYC 2011
Nice spinnaker lobe for the higher TWSs 76T! :-)

No TWA=0 line though - which turned out to be a good thing as it made me modify the polar Explorer to handle such files...
Any particular reason for not including it?? or a TWS=0 column?
Sure they are only zeroes but nedded for correct interpolation of high TWA's or very low wind speeds...
--------------------

Who wrote this post please?

--- Last Edited by RainbowChaser at 2011-06-07 08:35:08 ---

Page: 1 2 3 4 5 6 7 Next Last

Please login to post a reply.

Races

Next Race: 00d 00h 00m

Current Races:

Roslagen TIMED Sea Race

Welcome to quite possibly the most challenging TIMED race of the year. This month finds us in Sweden with lots of islands and narrow passages when we sail our Seacart 30 trimaran over the 86nm from Lidingö outside Stockholm to the beautiful coastal village of Öregrund. Consider yourself a winner if you complete the course nonstop! This is a TIMEDrace so you may RE-REGISTER HEREto try again after finishing a run. You will have 13 days and 11 hours to test your skill and decision making after the race opens.
Race #1945
INFO by brainaid.de
Seacart 30 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ3 - TRCH - SUPSOL - SYC
Race starts: Sep 07th 12:00 Registration Open!
▶ Flash
GO TO RACE

The Vineyard Race 2025


For the first time since first hosting a virtual Vineyard in cooperation with Long Island's Stamford Yacht Club back in 2010, due to an operational calendaring error, Sailonline has missed the start of the real life race, the USA’s Labor Day weekend this year unusually falling across the turn of August. Silly SOL! So, a week late please join us anyway for a virtual rerun of Stamford’s iconic annual overnighter from their club line out the sound to Buzzard's Bay Light near Martha's Vineyard Island and back again, leaving Block Island to starboard. This year, Sailonline is making its magic MC 38 available to competitors, a race boat with a quirky polar that will require you to stay wide awake as you speed around the c 250 nm course, in rockstar style!
Race #1946
INFO by brainaid.de
MC 38 PARTICULARS
NAM_AWIP WX Updates:
0245 / 0845 / 1445 / 2045
Ranking: SYC
RACE CLOSE: Sunday,
September 14 at 2300 UTC.
Race starts: Sep 06th 17:05 Registration Closed
▶ Flash
GO TO RACE

Great Nicobar to Marion Island 2025

The Adventure Continues – Leg #6 of the RWW Series.
We’re setting sail on the next stage of the RWW Series: a 4,400-nautical-mile passage from Great Nicobar to Marion Island. This demanding leg will test endurance, strategy, and seamanship at the highest level. As part of the 2025 Ocean Championship, this marks the ninth legendary challenge in the series — and one of the most exhilarating yet. The race will be contested aboard the Archer 78’ ketch, a vessel built to push sailors to their limits across the vast Indian Ocean.
PRIZE: SMPF
Race #1942
INFO by brainaid.de
Archer 78 PARTICULARS    
WX Updates:
0430 / 1030 / 1630 / 2230    
Ranking: OCQ3 - RWW - OCCH - SUPSOL - SYC
Race starts: Sep 01st 11:00 Registration Closed
▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member vida
  2. Sailonline Yacht Club Member WRmirekd
  3. Sailonline Yacht Club Member CriticalHippo
  4. Sailonline Yacht Club Member rafa
  5. Sailonline Yacht Club Member KaSToR
  6. Sailonline Yacht Club Member Kipper1258
  7. Sailonline Yacht Club Member BRENTGRAY
  8. Sailonline Yacht Club Member Sax747
  9. Sailonline Yacht Club Member Panpyc
  10. Sailonline Yacht Club Member CollegeFund

View full list

Series

Mobile Client

SYC members have the benefit of access to our mobile/lightweight web client!

The mobile client