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 » Technical Support » Bluewater soft

Page: Previous 1 2 3 4 Next

Posted by
Joshua_Pig


Users avatar

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
Posted by
Exmeromotu


Users avatar

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
Posted by
Exmeromotu


Users avatar

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
Posted by
sol


Users avatar

Posts
298
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


Users avatar

Posts
362
Registered at
2009-08-03 18:04:56
2010-07-20 13:03:43 - Re: Bluewater soft
Argh
Posted by
Joshua_Pig


Users avatar

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


Users avatar

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


Users avatar

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
Posted by
sol


Users avatar

Posts
298
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


Users avatar

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:

Falklands to Tasmania 2026

Welcome to yet another all-new route. This next race is part of our Ocean Championship as well as the ROW series. Falklands to Tasmania, is like last year's island to island. It’s one of the longer ones 6400nm, more than half way around the world (and the Antarctica). It starts the 2026 OCQ2, and will be sailed in our Steinlager 2, contrary to prior notice.
Race #2021
INFO by brainaid.de
Steinlager 2 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: OCQ2 - ROW - OCCH - SYC
Race starts: Apr 06th 11:00 Registration will open soon
▶ Flash
GO TO RACE

Gladstone Ports Corporation Brisbane to Gladstone Yacht Race 2026


Sailonline is thrilled to partner with the Queensland Cruising Yacht Club for the 2026 Gladstone Ports Corporation Brisbane to Gladstone Yacht Race! This 308 nautical mile offshore challenge follows Australia’s stunning east coast from Brisbane to Gladstone. Racing the fast and tactical Farr 40, sailors will need precision, strategy, and focus as shifting conditions test every decision from start to finish!
Race #2027
INFO by brainaid.de
Farr 40 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: SUPBUD - SYC
Race starts: Apr 03rd 01:00 Registration Open!
▶ Flash
GO TO RACE

Rapallo to Nador 2026


Welcome to Liguria’s Rapallo, there where Zarathustra spoke - at length - to Nietzsche, for our first race of nine to celebrate all things Mediterranean - fickle winds, history and olive oil. A number of our races in this new Magical Mediterranean series will be partnership with famous real-life races, but this first race is pure fiction - 780nm in refurbed IMOCA 60s, past or through the Balearic Isles and on into the Alboran Sea, to a finish off Nador on the Maroc Mediterranean coast.
Race #1975
INFOby brainaid.de
IMOCA 60v2 PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: MED - SYC
Race starts: Mar 30th 15:00 Registration Open!
▶ Flash
GO TO RACE

Cross the Convergence 2026 - Guam to Ouvéa


The third race of our series of ocean voyages across the World’s convergence zones takes us southeastward now down the Pacific, from Guam’s Apra Harbour at 13.5 degrees North, back across the Equator to the glorious New Caledonian resort island of Ouvéa, on the edge of the Tropic of Capricorn at 20.5 degrees South. It’s 2400nm, and there’s more than a few other islands in the way, so mind where you go in your Ocean 50s. Race #1981
INFOby brainaid.de
Ocean 50PARTICULARS
WX Updates:
0430 / 1030 / 1630 / 2230
Ranking: CCZ - SYC
RACE CLOSE: Tuesday,
April 7 at 2300 UTC.
Race starts: Mar 20th 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 WRmirekd
  3. Sailonline Yacht Club Member rafa
  4. Sailonline Yacht Club Member rumskib
  5. Sailonline Yacht Club Member Panpyc
  6. Sailonline Yacht Club Member CollegeFund
  7. Sailonline Yacht Club Member Sax747
  8. Sailonline Yacht Club Member CriticalHippo
  9. Sailonline Yacht Club Member vida
  10. Sailonline Yacht Club Member sassy63

View full list

Series

Mobile Client

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

The mobile client