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 / SOLstice Cup

Page: 1 2 Next

We missed IMSYC this year!

Luckily, Jakob has thoughfully provided as a tool to run our own at www.polardesigner.org, an online parametric Velocity Prediction Program (VPP) where we can play at designing our own fleet. Clear your desk, break out your Marchaj and dust off your ducks - it's time to do some designing.

Due to the constraints of the methods used in the VPP, we can't start off with J-Class Masterpieces (I know, I know) and the Twelves fall just outside what is sensible. Some of the smaller Universal-Rule boats would suit, but I suggest we set our sights on the deservedly popular International-Rule 8 Metre class.



http://8mr.org.uk/history/history-8m2000rules.pdf

Thinking out loud, but I'm imagining a fleet race/miniseries hosted by the challenger of record to select the match boat, followed by a two boat(type) race vs defender. In order to keep numbers to manageable levels, countries/regions will collaborate to field a single design.

Suggested grouping for 5 groups of roughly equal size.

Nordic
Pan American
North Sea (minus Norway)
Western Mediterranean
ROTW

Individual boats could choose from the fleet - no need to stick with own region if that doesn't appeal. Other options open for discussion! Not sure how much interest there might be, but I think we need to keep the numbers reasonable. I'm happy to do the final prep to get the designs out of polardesigner and cleanly into SOL.

We could make the race non-point scoring (or make a seperate ranking).

Attached is a spreadsheet that does the grunt work of calculating the Rating. All that is needed is to transfer the numbers from polardesigner. Polardesigner gives warnings when a value is out of bounds for the algorithm, and the spreadsheet should ensure that the boats conform to rule. It probably needs cleanup. Any guinea pig Herreshoffs out there?

The authours issued a public call for beta testers and feedback. I figure we have an obligation and the weather gauge - prepare for broadsides!

Speak up in this thread - yay or nay?

76T
Attachments
Just for your amusement, 76, I actually sail an 8 Metre yacht,"Gracia". built to the old rules. Mine is of course radio controlled, in the 36-600 class of model yachts. It was originally a 36 Inch long kit by the German model company, Graupner, and the hull is all wood and wood planked. I cut the long keel off and replaced it with a fin and bulb, because the original design just lay down on it's side in any wind at all. As the 36-600 class isn't used in North America, I eventually changed the rigging to a schooner with removable topsails and a flying jib as the third headsail, all controlled by one sail servo. She sails very well and really looks 'scale' on the water.
As the name 'Bluenose' was already taken, and the further name 'Rednose' also, I was forced to call her "Runnynose"----after myself, of course.
If it breaks, it's not strong enough--if it doesn't, it's too heavy.
I'm in even though I don't know what I'm doing.

Will try to learn as much as I can & have fun.
None so blind
I like the idea. Count me in.

Question:

Are we going to know the race location and circuit before designing the boat?
So, we could taylor made the design; i.e. racing on a predominate light or strong wind location, mostly head or down wind?

or,

We should design an all around yacht and the races would have upwing, downwind and reaching legs ?

Another option is to use the old "Ton Cup" world championship formats; (3) short races, max 24hrs, (1) Overnight race, max 48hrs and (1) Long race, max 72hrs.
All races count, short races weigh 1 point, medium race 2 points and long race 3 points.


I think, this can really be exciting.

Antonio (zero)


Are we going to know the race location and circuit before designing the boat?

So, we could taylor made the design; i.e. racing on a predominate light or strong wind location, mostly head or down wind?

We should design an all around yacht and the races would have upwing, downwind and reaching legs ?

Use the old "Ton Cup" world championship formats

I think, this can really be exciting.
.

Yes - deed of gift etc... half the point :-) I think it would be up to the challengers to find a representative course for trials. Volunteers for CoR? :-)

Yes!!

Yes

Yes?

*YES* woooooo!!! (imho)
I realize there are many details to be worked out but if practical I would advocate for the opportunity to sail at least 1 preliminary round (sub groups if necessary) in self designed boats.

P.S.

I have your SS & have opened the polar applet but it still may take a little further explanation.

Questions I have :

Are all the variables components of the 8 Metre formula or are there some dimensions that only affect the polar configuration but not the main Rule ?

Does the Freeboard parameter refer to keel & rudder dimensions ?

What do the cells in your SS with Red backgrounds signify ?

--- Last Edited by Hubert Bonisseur at 2011-05-01 14:22:11 ---
None so blind
Are all the variables components of the 8 Metre formula or are there some dimensions that only affect the polar configuration but not the main Rule ?

Does the Freeboard parameter refer to keel & rudder dimensions ?

What do the cells in your SS with Red backgrounds signify ?
Good questions. The parent hullforms used to build the VPP are based on relatively modern ~40 footers, while the International Rule produced long overhangs and wineglass sections. The length L used for rating normally has corrections made to it that partially take into account hullshape. The VPP produces results assuming that we're all sailing more or less the same basic shape (stretched this way and that), so I left out the extra length complexity and just used the minimum form the rule.

So - normally the Prismatic Coefficient (CP in polardesigner) and the longitudinal centres would show up in L.

Midship Coefficient (CX) would show up in the Girth correction "d". The model isn't really suitable for deep hulls/full keels, but the spreadsheet approximates the girth calculation using a circular submerged section through the BWL and hull depth points. Using an arc is pretty close for the range of CX allowed, but it means that CX doesn't show up in the rating.

SO... free pass on CX, CP, LCB and LCF. Note that they do affect displacement for a given LWL/Beam.

None of the appendage inputs are rated, but draft must meet the rule. CG for the ballast can go right to the end of the keel, which isn't quite right, but works fine.

All of the sail inputs end up in rated sailarea except spinnaker leech length and mast diameter, for which a min/max are defined. Spin leech length might be defined differently in polardesigner, so the range might need adjusting.

Freeboard is the average height from waterline to deck.

The red cells are values out of range. Either outside of the rule or physically impossible.
Regarding IMSYC: If you are interested in the rule for the IMSYC race 2011 you can find it here http://www.kth.se/polopoly_fs/1.47075!IMSYC-66%20rule.pdf
I have about ten students designing boats for the race :-))

/Jakob
...one of the guys behind the game...
Great news that we get an IMSYC this year, and the 2011 rules look to produce some nice racing :-)

I'd figured that term-end had come and gone!
...and if you want to play around with hull shapes etc to investigate effects on CP, trim, stability etc you might want to try the msy_hydrostatics-code that I put on the same web-page. The code lets you import hull shapes and then stretch them in various ways :-)
...one of the guys behind the game...

Page: 1 2 Next

Please login to post a reply.

Races

Next Race: 00d 00h 00m


Current Races:

Iliamna Lake, Alaska 2023

In search of wind and ice, we traveled as far as Alaska. Here on Lake Iliamna we will have our next ice race. Round the lake 145nm circuit counterclockwise in the DN ice boat. High speeds are expected so fasten your seatbelts and put on your goggles. Please note that there is no Performance Loss.
Race #1663
INFO by brainaid.de
DN ice boat PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: DN - SYC
Race starts: Feb 11th 15:00 Registration will open soon

▶ Flash
GO TO RACE

Aland Sea TIMED Race 2023
Norrtalje Segelsallskap, 70km NE of Stockholm was founded in 1920, and time was when the society’s season opened with a challenging offshore race from the club line off Flaten island at the mouth of the long and narrow Norrtaljeviken, out onto a triangular course around the Aland Sea, to finish at Simpnas slightly to the north on Bjorko island - some 78nm in total. This will be the 6th time that SOL is running this race, and just like its previous iteration almost exactly 2 years ago will be held as a TIMEDrace in pretty Club Swan 50s.
RE-REGISTER HERE to race again after finishing a run
Race #1651
INFO by brainaid.de
Club Swan 50 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ1 - TRCH - SUPSOL - SYC
RACE CLOSE: Sunday, 26 February at 23:00 UTC
Race starts: Feb 11th 12:00 Registration will open soon

▶ Flash
GO TO RACE

Melbourne to Hong Kong
After celebrating Christmas and New Year it is time for the second run in this year's Ocean Race Championship. After leaving Melbourne on this (about) 5.500 NM course, we will leave the Solomon Islands, Papua New Guinea and the Philippines, all to port. And remember, once again we'll have to choose the best way to cross the Doldrums
PRIZE: SMPF
Race #1658
INFOfrom brainaid.de
OD65v3 Particulars
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
OCQ1-OCCH-SUPSOL-SYC
Race starts: Feb 04th 05:00 Registration Open!

▶ Flash
GO TO RACE

Buenos Aires to Rio 2023

This year's second ARCH series race will run from Buenos Aires, Argentina to Rio de Janeiro, Brazil on a route designed by SOLer Vida_Maldita (under his former alias of zero) in 2013. This is a replica of a classic triennial race of 1200nm, first run in 1947. More information about this IRL race can be found here.
So, Bemvindo/Bienvenidos in this coastal classic and prepare your 90ft Monohulls well.
Race #1662
INFO by brainaid.de
90ft Monohull PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
ARQ1 - ARCH - SUPSOL - SYC
RACE CLOSE: Sunday,
February 12 at 2300 UTC.
Race starts: Feb 01st 18:00 Registration Closed

▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member WRmirekd
  2. Sailonline Yacht Club Member Pit8008
  3. Sailonline Yacht Club Member FreyjaUSA
  4. Sailonline Yacht Club Member Vida_Maldita
  5. Sailonline Yacht Club Member Kipper1258
  6. Sailonline Yacht Club Member bonknhoot
  7. Sailonline Yacht Club Member Sax747
  8. Sailonline Yacht Club Member SlideRule
  9. Sailonline Yacht Club Member TarassBoulba
  10. Sailonline Yacht Club Member rafa

View full list

Series

Mobile Client

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

The mobile client