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 » Real Life Honesty Race question

Page: Previous 1 2 3 4 Next

Posted by
NOR_Jawik


Users avatar

Posts
70
Registered at
2008-08-31 20:55:18
2011-04-14 12:04:54 - Re: Real Life Honesty Race question
Gilles said @ 2011-04-14 08:27:29:
Am I crazy?
No you are not. Fix course on Lat/Lon and no rumbline. I like it.
Posted by
BER_Baggus


Users avatar

Posts
70
Registered at
2008-12-26 18:46:10
2011-04-14 14:58:57 - Re: Real Life Honesty Race question
@Gilles & 76 - to be honest, the course is probably too short, only a few hours long. What I was after is what wind direction would be best for our polars. I'll see if I can all the GPS coordinates.
Posted by
76Trombones


Users avatar

Posts
362
Registered at
2009-08-03 18:04:56
2011-04-14 15:15:21 - Re: Real Life Honesty Race question
It's a good exercise! It's not the same as ocean-racing routing, but the tools are similar. Even without shifts and predictors and gribs and such, just identifying favourable prevailing wind conditions is a useful trick.

Totally doable with a spreadsheet. To make life easier for such things it's helpful to fill the area between VMGs (and any other hollows) so that you don't need to worry about tacking.
Posted by
BER_Baggus


Users avatar

Posts
70
Registered at
2008-12-26 18:46:10
2011-04-14 20:45:46 - Re: Real Life Honesty Race question
It's totally doable with a spreadsheet, assuming someone has that spreadsheet...... ;-)

The routing software is good, but it would only show you the optimum course for the forecast winds. I want too see what the best wind direction would be so that when, probably in 4 months time, it actually blows from that direction, we can make the best time. If that makes sense.
Posted by
Smo


Users avatar

Posts
80
Registered at
2009-05-02 21:49:04
2011-04-15 06:03:52 - Re: Real Life Honesty Race question
Should be quite obvious on just cheking wx no need for routers more tricky to get crew there in right time. And good sailing makes it.

--- Last Edited by Smo Smo at 2011-04-15 06:05:01 ---
Posted by
76Trombones


Users avatar

Posts
362
Registered at
2009-08-03 18:04:56
2011-04-15 19:57:47 - Re: Real Life Honesty Race question
I was going to show how to do this just with pen and paper, but here's an example spreadsheet. Change the leg angles and lengths. This is both clumsier and more complicated than necessary, but maybe can tell what is going on.

;-)
Attachments
Posted by
A2


Users avatar

Posts
347
Registered at
2009-10-26 00:39:42
2011-04-15 20:15:00 - Re: Real Life Honesty Race question
I am quite interested in All pen & paper solutions to the various sailing conundrums that encompass navigational exercises.

Please show your work :)

P.S.

When I open the .xls file in NeoOffice I get get a series of #ADDIN? errors for the Spline computation in the field as well as the final Best TWD & Fastest Time



--- Last Edited by Hubert Bonisseur at 2011-04-15 20:22:53 ---
None so blind
Posted by
76Trombones


Users avatar

Posts
362
Registered at
2009-08-03 18:04:56
2011-04-15 20:33:38 - Re: Real Life Honesty Race question
In words:

Convert your polar from knots to minutes/nm. For each leg, multiply the polar by the leg length and transfer to a plot using your dividers. The curve for each leg is added to the one preceding it. The resulting plot reads time, so your best TWD is the minimum.

Here is the data used in the spreadsheet example - the fastest angle in 12kt wind is ~214 degrees.

Course Leg 1 Leg 2 Leg 3 Leg 4
CC 0 45 270 130
NM 3 2 4 5


1/4 Ton 6 8 10 12 14 16 20
52 4.41 5.21 5.75 6.06 6.23 6.34 6.45
60 4.70 5.48 5.97 6.28 6.50 6.62 6.75
75 4.98 5.85 6.33 6.63 6.77 7.01 7.23
90 5.24 6.01 6.48 6.85 7.13 7.27 7.59
110 5.03 5.82 6.32 6.75 7.14 7.55 8.23
120 4.74 5.60 6.16 6.59 6.99 7.40 8.38
135 4.15 5.10 5.80 6.26 6.67 7.05 7.93
150 3.51 4.47 5.25 5.86 6.30 6.68 7.43

Bangle 43.4 42.0 40.4 40.9 40.0 39.3 39.4
BVMG 2.87 3.48 3.87 4.13 4.28 4.38 4.46

Rangle 146.6 152.9 161.6 167.0 172.9 174.7 175.2
RVMG 3.04 3.87 4.62 5.27 5.81 6.22 6.93
Posted by
76Trombones


Users avatar

Posts
362
Registered at
2009-08-03 18:04:56
2011-04-15 20:42:54 - Re: Real Life Honesty Race question
When I open the .xls file in NeoOffice I get get a series of #ADDIN? errors for the Spline computation in the field as well as the final Best TWD & Fastest Time
-

Yes the posted example uses a plugin for the interpolation functions and I don't think OpenOffice handles it correctly. Hmm...

There's a cubic spline function posted at oooforum.org. Very much worth looking into for sailing spreadsheets. I used a second function to find the minimum, but there areother ways to do that.
Posted by
Rod


Users avatar

Posts
392
Registered at
2010-06-24 22:30:48
2011-04-15 20:49:32 - Re: Real Life Honesty Race question
Duuuuh!!! Now I'm feeling stupid! I even taught coastal navigation for a while in the Navy but I do not have any idea what would be needed to get any info out of your spreadsheet. Hands up! How many SOLers know how to do this?
Sorry 76T, but its got to be simpler than that to help ME.
If it breaks, it's not strong enough--if it doesn't, it's too heavy.

Page: Previous 1 2 3 4 Next

Please login to post a reply.

Races

Next Race: 00d 00h 00m

Current Races:

Cape Town to Java 2025

Get ready for an exhilarating new challenge as we set sail on the eighth leg of the 2025 Ocean Championship Series! Reversing the 18th century footsteps of the indentured Cape Malays that inspired Isna Marifa’s moving novel 'Mountains More Ancient' , this leg takes us from Cape Town South Africa to the Bay of Belbuhan on the south west coast of Java - a 5100 nm journey of endurance, strategy, and pure sailing adrenaline, aboard the 125 ft Orange catamaran. Do you have what it takes to conquer the Indian Ocean? Join us and put your skills to the ultimate test!
PRIZE: SMPF
Race #1937
INFO by brainaid.de
Orange 125 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ3 - OCCH - SUPSOL - SYC
Race starts: Aug 04th 11:00 Registration Open!
▶ Flash
GO TO RACE

Lago Viedma Ice Race 2025


Less than one third of the land mass of the planet is to be found in the southern hemisphere, and most of that in tropical to temperate latitudes or in Antarctica, so it is difficult to find good natural ice to race DNs anywhere in August! However, if you take an internal flight from Buenos Aires to Aeropuerto Internacional Comandante Armando Tola de El Calafate by the shores of Lago Argentino, it’s only a 100km taxi ride to Lago Viedma, where we have set out a few beacons on the ice for you for a quick 80nm blast around the four corners of the lake, and as it’s so remote here, no need to worry about breaking the solitude of monks or suffering PL!
Race #1852
INFOby brainaid.de
DN PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: DN - SYC
Race starts: Aug 03rd 09:00 Registration Open!
▶ Flash
GO TO RACE

Tall Ships Races 2025 - Kristiansand to Esbjerg


Welcome to the fourth of four virtual Tall Ships Races in European waters which are concurrently being organized in-real-life by Sail Training International . This fourth race is from Kristiansand in Norway down Denmark’s North Sea coast to Esbjerg; circa 150nm in Sailonline’s magnificent 90m Barque.
NOTE: Starts and Finishes in tall ships racing are always offshore to avoid conflict with shipping and shipping lanes; online and real-life may not match exactly.
Race #1926
INFO by brainaid.de
Barque 90m PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: TS - SYC
Race starts: Aug 02nd 16:00 Registration Open!
▶ Flash
GO TO RACE

Marstrand to Cowes 2025


We invite you to another race, which will kick off the third quarter of our ARCH series. We'll set off from Marstrand, Sweden, which, along with Skagen, Denmark, marks the line commonly recognised as the border separating the Baltic Sea from the North Sea. The 650nm route will take our Ripitide 50 across the North Sea and the English Channel to Cowes, England. Watch out for the fast ferries crossing the Channel from Calais to Dover 😊.
Race #1935
INFO from brainaid.de
Riptide 50 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
ARQ3 - ARCH - SUPSOL – SYC
RACE CLOSE: Wednesday,
August 6 at 2300 UTC.
Race starts: Jul 28th 17:00 Registration Closed
▶ Flash
GO TO RACE

Sinbad by Balloon 2025 - Baia de l'Oiseau to Carnarvon


How ever shall I return to report with clarity to my Great Sultan – asked Sinbad. It needs be told this island and all its fables shall be expunged from the annals of every thousand and one night. The wind howls – and sun be none (it’s Winter, Sin’bro, ed.) – and all days from the west, but let’s launch anyway and see if we can work our SOL Balloon north as the days pass aiming for Asthralaya, where The Mahabharata tells the ancients once tested mighty weapons, about a quarter and a million qasbah away (2500nm, ed.), perhaps one month.
Race #1885
INFOby brainaid.de
SOL Balloon PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SYC - SBB
RACE CLOSE: Sunday,
August 10 at 2300 UTC.
Race starts: Jul 23rd 11:00 Registration Closed
▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

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

View full list

Series

Mobile Client

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

The mobile client