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:

Mad Max by Balloon 2026 - Across the Outback


Mad Max Rockatansky doesn’t get to go in a balloon in any of the Legends of the Wasteland, and the Wasteland is not necessarily the Outback of Australia, but Mel Gibson and film director George Miller indubitably are… of Australia, and ballooning as reconnaissance is a main feature of the Mad Max spin-off video game, so here goes: 1500nm in a balloon from somewhere on the edge of the Outback, Goondiwindi, to cross a finish line at Fitzroy Crossing, somewhere on the edge of the Outback!
Race #1974
INFOby brainaid.de
SOL Balloon PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: BOL - SYC
Race starts: Oct 14th 13:00 Registration will open soon
▶ Flash
GO TO RACE

Valdes Peninsula TIMED Race 2026

October finds us on the Argentina coast for the Valdes Peninsula race. A UNESCO World Heritage Site the peninsula is a breeding ground for southern right whales. Sail the luxurious blue water Delphia 47 around a 160 nm course in an attempt to turn in the fastest time.
This is a TIMEDrace so you may RE-REGISTER HEREto try again after finishing a run. You will have two weeks to test your skill and decision making after the race opens.
Race #2066
INFOby brainaid.de
PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ4 - TRCH - SYC
RACE CLOSE: Saturday,
24 October at 23:00 UTC
Race starts: Oct 11th 12:00 Registration will open soon
▶ Flash
GO TO RACE

Roma Giraglia Regata 2026

Our eighth race of nine to celebrate all things Mediterranean - fickle winds, history and olive oil – is another buddy-up; this one with the Circolo Nautico Riva di Traiano . Founded in 1984, as the new Traiano yacht Harbour neared completion, the Circola since then has developed into one of the major yachting competition centres in Italy, and next to the 450nm Roma per Tutti (which SOL buddied earlier in the year), the Roma Giraglia Regata is its other headline offshore event. First raced in 2005, the 210nm course takes competitors from Traiano to a rock on the inside of the Ile de la Giraglia off the northern tip of Corsica and back to the Italian mainland for a finish in the bay of Santo Stefano. We’re racing this one in our Class 40!
Race #2058
INFO by brainaid.de
Class 40 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: MED - SUPBUD - SYC
Race starts: Oct 08th 16:00 Registration Open!

▶ Flash
GO TO RACE

Arctic Tern - Greenland to Antarctica 2025

Welcome to the fifth leg of our MIG series. Now it's time to race the Arctic Terns, on their migration from Greenland to Antarctica, 8300 NM. This is also part of our monthly Ocean Championship, and as such the first race of OCQ4 2026. This race will be sailed in our Maxi Trimaran. Race #2061
INFO by brainaid.de
Maxi Trimaran PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230 Ranking:
OCQ4 - OCCH - SYC - MIG
Race starts: Oct 05th 11:00 Registration Open!
▶ Flash
GO TO RACE

Cross the Convergence 2026 - Masirah to Chagos


Having crossed, re-crossed and re-re-crossed the Convergence Zones of the Pacific and the Atlantic, we now face our second crossing of the Convergence Zone of the World’s third great equator-spanning sea, the Indian Ocean, taking us from the channel between Masirah Island and the Oman mainland to the Chagos Archipelago. It’s 1900nm and we’ll be sailing our very fine Archer 78, and won’t mention that both locations (of departure and arrival) are heavily militarized and the why’s and what next’s concerning that – mindful as always of SOL Netiquette.
Race #1988
INFOby brainaid.de
Archer 78PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: CCZ - SYC
Race starts: Oct 02nd 18:00 Registration Closed
▶ Flash
GO TO RACE

Go to race archive

SYC Ranking

  1. Sailonline Yacht Club Member KaSToR
  2. Sailonline Yacht Club Member CriticalHippo
  3. Sailonline Yacht Club Member WRmirekd
  4. Sailonline Yacht Club Member rafa
  5. Sailonline Yacht Club Member rumskib
  6. Sailonline Yacht Club Member Panpyc
  7. Sailonline Yacht Club Member cdhinman
  8. Sailonline Yacht Club Member rthinman
  9. Sailonline Yacht Club Member BRENTGRAY
  10. Sailonline Yacht Club Member Sax747

View full list

Series

Mobile Client

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

The mobile client