Sailonline.org - Online Sailing

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!

Tweets by @sailonline

Board » Technical Support » Bluewater soft

Posted by Joshua_Pig Posts 22 Registered at 2009-09-25 16:58:15	2010-07-20 09:02:09 - Re: Bluewater soft
	Hi Exmer, I still don't understand why I have so much differences between Sol and BW wind... so I tried to make it work for the Chicago-Mckinac race. 1st file shows you what I got with Brain's file, 2nd one with Ugrib file The 3rd one is what I got after having removed and reinstalled BW entirely... still no improvement ! What can I do wrong ? Thanks a lot Attachments Chicago.JPG (269.8 KB) Chicago2.JPG (282.3 KB) Chicago3.JPG (218.7 KB)
Posted by Exmeromotu Posts 71 Registered at 2008-12-10 15:22:17	2010-07-20 10:58:25 - Re: Bluewater soft
	Joshua, I will look into it. I haven't gone to the Chicago Mac race area yet so I don't know what the weather is like. But I kept doing my Expedition and Bluewater comparison on the Scurry race with interesting results. I used brainaids grib files for both software programs. I modified Bluewaters polars as per Bluewaters manual ( The 2nd TWA in a line is the best VMG upwind angle for that windspeed. The 2nd to last TWA is the best VMG downwind angle for that windspeed). Once again expedition had to be "coaxed" into routing on water with the addition of exclusion zones. Miraculously Bluewater routed over water, and didn't hit any land! I selected the Scurry race at this time because of the upwind scenario and a shift that required navigate close to land to see how each software performed. No human intervention. Bluewater tended to use better upwind angles than Expedition with the Bluewater routed boat getting to Sea Lion island nearly 1 mile directly upwind of the Expedition boat. Expedition liked to point a more into the wind than necessary, however both softwares had strectches with crazy TWA's (25 deg.) Attached is a pic of the comparison. Later today I will do the comparison downwind to see how they perform on the gybing angles. The blue track is the Bluewater boat (Green Onions) the red track is the Expedition boat (Exmeromotu). Both programs interpolated the wind extremely close to the SOL wind. Cheers Attachments BW_Exp_Comparison.jpg (178.2 KB)
Posted by Exmeromotu Posts 71 Registered at 2008-12-10 15:22:17	2010-07-20 11:47:24 - Re: Bluewater soft
	Joshua Your case is a mystery to me! I went to the Chicago Mac race and the weather from Bluewater is pretty much the same as SOL's. Check the attached pics with weather readings at the start mark. SOL weather at 12 Z on Start Mark: 3.3 kts @ 242 BW weather at 12 Z on Start Mark 3.4 kts @ 243 These are the "cursor" readings at the location. For Bluewater I used brainaids grib file weather_51_global_gfs_20100720_1030.grb BW weather reading at cursor is in the picture at the lower right hand corner. SOL weather reading at cursor in the picture at upper right hand corner. Cheers --- Last Edited by Exmeromotu at 2010-07-20 11:55:05 --- Attachments Chi-Mac_SOL_weather.jpg (276.9 KB) Chi-Mac_Bluewater_weather.jpg (159.8 KB)
Posted by sol Posts 296 Registered at 2008-08-14 11:08:14	2010-07-20 13:01:54 - Re: Bluewater soft
	Huh - I didn't know that brain's weather was sol weather. It works perfectly for me as well. A couple of ideas: Bluewater does strange things interpolating the weather timewise. The default timestep is 3h or so. I don't know how much penalty you pay for reducing this, but anything more than ~10m is going to cause problems. There are about 6 different places to select zulu time and true North... Exmer - when you are seeing angles inside VMG in Expedition are they in ()? Most routing allows for a tack or gybe on a leg, which exp indicates with brackets. The twa is the average. Watch out for the above on polar-hops as well.
Posted by 76Trombones Posts 362 Registered at 2009-08-03 18:04:56	2010-07-20 13:03:43 - Re: Bluewater soft
	Argh
Posted by Joshua_Pig Posts 22 Registered at 2009-09-25 16:58:15	2010-07-20 17:01:43 - Re: Bluewater soft
	Thanks again Exmer and 76, I did everything I could imagine to get the right wind, but there is still very big differences between Sol and BW datas... Did you change something after the installation of BW in the settings for the grib files ?
Posted by Exmeromotu Posts 71 Registered at 2008-12-10 15:22:17	2010-07-20 20:09:15 - Re: Bluewater soft
	Joshua, Go to the Tools menu on Bluewater, select Preferences, on that window check your time as Zulu time and click Save. I have all my settings and all my inputs are in ZULU time, it just makes it easier. Make sure all your times are in Zulu time on the Route Manager and on your individual routes. Now load a grib file (preferably the one from brainaids site due to its relationship with SOL weather) and verify that the weather matches. The only reason for your weather not matching must be that your date and time are out of whack somewhere as 76T implies. Let me know a day and time that time you are active on the chat so we can work through it. Regards,
Posted by NZL_undercover Posts 65 Registered at 2009-07-31 03:29:32	2010-07-20 20:15:28 - Re: Bluewater soft
	Hi 76, What do you mean by Polar Hops? Here's a picture of Expedition how I have it set up with Brainaides info feeding into it. Cheers Undercover Attachments Expedition_2.JPG (331.9 KB)
Posted by sol Posts 296 Registered at 2008-08-14 11:08:14	2010-07-20 20:57:27 - Re: Bluewater soft
	We try to avoid sailing in any "dent" on the polar, like the one that typically shows up ~120 between up and downwind sail suits. Last entry on 76trombones.wordpress.com has a quick discussion. If you are using a 10m timestep and the routing wants you to sail 150 for 5m and 90 for 5m, it'll return 120twa. No blindly following the numbers! Different software deals with this (and the upwind cases etc) in different ways. Obviously none of the commercial ones are intended for sailing with "perfect" wind, so to-the-second timing isn't really necessary. That's quite the tactical setup!
Posted by Green_Onions Posts 2 Registered at 2010-05-20 17:29:32	2010-07-20 21:02:27 - Re: Bluewater soft
	Sorry It's Exmer didn't notice that 76T had already answered your question UC. Cheers!! --- Last Edited by Green Onions at 2010-07-20 21:18:30 ---

Page: Previous 1 2 3 4 Next

Please login to post a reply.

Races

Next Race: 00d 00h 00m

Current Races:

Kapiti Chetwodes Race 2024

For only the second time in SOL history, we have the pleasure of inviting you to the Kapiti Chetwodes Race, held in the Cook Strait region. Organised IRL by the Royal Port Nicholson Yacht Club from Wellington in New Zealand. The approximately 160nm long route, full of turning points, will take us from the bay at RPNYC around the islands of Somes, Kapiti and Chetwodes and back to the finish line at RPNYC. We have only a 26 ft Albin 79 yacht at our disposal. All this means that we will have a lot of fun, so fair winds!
Race #1864
INFO by brainaid.de
Albin 79 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
ARQ4 - ARCH - SUPSOL - SYC
Race starts: Nov 25th 17:00 Registration Open!

▶ Flash

GO TO RACE

Raja Muda Selangor 2024 - Penang to Langkawi

Welcome to the third and last online race of the Raja Muda Selangor International offshore series – a 70nm final trip further north again up the Malacca Strait from Penang to the exotic island of Langkawi, and again in Ker 40s.
Race #1871
INFO by brainaid.de
Ker 40 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: RMS - SYC
RACE CLOSE: Monday,
November 25 at 2300 UTC.
Race starts: Nov 21st 04:00 Registration Open!

▶ Flash

GO TO RACE

Raja Muda Selangor 2024 - Pangkor to Penang

Welcome to our second online offshore race in cooperation with Raja Muda Selangor International – an 80nm trip from Pangkor north to Penang up the Malacca Strait, again in Ker 40s.
Race #1870
INFO by brainaid.de
Ker 40 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: RMS - SYC
RACE CLOSE: Saturday,
November 23 at 2300 UTC.
Race starts: Nov 18th 04:00 Registration Open!

▶ Flash

GO TO RACE

Two Oceans Doublecross TIMED Race 2024

Our November Timed race takes us to Cape Town near where the Atlantic and Indian oceans meet. Our ride is a beautiful ketch, the Archer 78. Starting at Cape Town, we’ll round Robben Island, then head south to round Cape Point, up around Seal Island before heading north to round Dassen Island before returning to Cape Town. This is a TIMED race, so you may RE-REGISTER HERE to 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 #1872
INFO by brainaid.de
Archer 78 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking:
TRQ4 - TRCH - SUPSOL - SYC
RACE CLOSE: Saturday,
30 November at 23:00 UTC
Race starts: Nov 17th 12:00 Registration Open!

▶ Flash

GO TO RACE

Nassau to Bodo 2024

Prepare for the grand finale - the 6th and concluding leg of the RTW challenge, an odyssey from Nassau in the Caribbean to Bodø in Norway. Embracing a journey of 4000 nautical miles, this leg promises an exhilarating 18-day voyage. It also heralds the November installment of our prestigious Ocean Race Championship. Embark on a voyage of a lifetime, where prowess, tactics, and camaraderie unite in the pursuit of triumph. We eagerly await your presence at the starting line! May the winds be ever in your favor.
PRIZE: SMPF
Race# 1866
INFO from brainaid.de
Swan 65 PARTICULARS
WX updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ4 - OCCH - RTW - SUPSOL - SYC
Race starts: Nov 11th 11:00 Registration Closed

▶ Flash

GO TO RACE

Go to race archive

SYC Ranking

View full list

Series

Mobile Client

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

The mobile client