Free Routing Software. qtVlm

[rgleason]

By the way the thread http://www.cruisersforum.com/forums/...-86443-19.html (to and from Opencpn), has a lot of information about the program, replies by Maitai, detailing how parts of the program work. Searches on that thread will bring up explanations.

[kiwisails]

All - Thanks all for the information, and the pointers to other threads. I will have a look and run some simulations now that I have a little bit of a better understanding, Happy sailing!

[rgleason]

Re: Term Crank. I always thought that was the result of the virtual racing mode, where the race proceeds in "cranks" (as if turning the crank on early mechanical computers) where everyone's position is calculated and boats move forward (or backward) in accordance with the polar, grib records of their immediate weather and their settings. Then there is a pause where the boat locations do not move, until the next "crank".

I can only quess how long it takes to do 1500 boat calcs, but adding the hits on the server by users wanting to know where they are in the race and to see the fleet, it probably is a very busy server and internet connection during big races.

[kiwisails]

Rgleason (Rick)

One quick question - at least I hope its quick. I see you spent a lot of time looking at Polar calculation applications. And as I was looking to pre-calculate my Polars as a baseline then validate. I was wondering on your search of the various tools that I saw you had posted on in 2012, what your end conclusion for a recommended tool to do the job would be.

I should say that I am NOT going to be racing my Endeavour 33 , but was looking to get the polars to assist with the routing calculations for cruising across the Gulf Stream etc. So a margin of error can be a little broader than my fellow countrymen taking on Larry Ellison in the AC.

I looked at the PCSail xls but that seems to have issues running on later versions of Excel ie. 2010 than it was built for ie 2000. There was a myriad of other applications free and paid, which one do you think is best based on your search.

[sinbad7]

maitai..

I am trying to create an optimized route using a stream .grib file (Current_gb_20121209.grib).

The map displays the arrows of the currents but I am unable to create a route from the Routings menu as I am unable to set the right departure date/time.

I have tried setting the departure as both 09/12/2012 00:30:00 UTC as shown at the top of the screen,and 12/09/2012 00:30:00 UTC without any luck.

Please advice what I am doing wrong..

Regards

Tore

[rgleason]

Kiwisails,

There are four ways to get polars that I know of:
1. VPP Calculated from the boat specs using VPP programs. PCsail is a spreadsheet version of that. It will give you a decent set of polars for your boat to start with, then you will want to adjust them for various physical boat changes, sea conditions, sail sets, actual weight, barnacles, etc.
2. Recorded from calibrated instruments through a Nmea bus connection to the PC using a Polar program intended to record the data.
3. Record the data by hand, making note of wind direction & wind speed, boat speed, sea and sail conditions, current, etc. This is an organized way of recording what you already know from experience about your boat, and it can be very effective if you approach it methodically, picking good conditions, knowing currents or finding slack tide, and getting good long runs with constant conditions if possible.
4. Get polars from a friend who has the same boat.

There are paid programs such as Expedition, Maxsea and Ocham which have polar recording and averaging built in.

PC Programs for Polar (open) Polauto and NavMonPC for that matter you could use Opencpn to record the data, and try using Konni's new Polar plugin to create polars.

If you have a nmea output with apparent wind speed and direction (true would also be good but not necessary), gps and speedo, you can connect your PC and record the data with NavMonPC or with Polauto. If you record with NavMonPC saving files, you can then run chosen file segments with specific conditions through Polauto and generate polar data. You can also use Polauto to record the data and create the polar at the same time. Polauto has a number of user settings that will enable filtering and averaging of data on a given run, to get a good plot. These user settings are very useful, because the wind varies a lot, as does boat speed and heading (less so). (Also you need to pick good times for recording and devote attention to that task so you get good runs with clean data.)

This is the first full summer season for Polauto in its current state, and I am hopeful that people are finding it very useful. I worked with Patrick to improve his program, and I hope that after the summer he'll have a host of users ready to make suggestions and improve the program, maybe simplify it a little based upon experience. I have tested it using Opencpn streaming Nmea data to Polauto via a COM port, and NavMonPC reading the Nmea data file and sending it to Opencpn, and have been able to give Patrick some suggestions and ideas.
http://www.cruisersforum.com/forums/...nts-96383.html
Now Polauto will read nmea data files itself, as well as accept a nmea data stream through a COM port.

I would suggest trying Polauto which is a Windows program. See the end of this thread. http://www.cruisersforum.com/forums/...s-89998-4.html

Polauto - translated - download is on this page.
Google Translate

Also, don't discount the Opencpn - Polar plugin by Konni. It is probably nice and simple and works well, but I have not tested it yet.

Of course you could contact Endeavor and as them for VPP calcs and Polars for your boat, often the manufacturer or designer may have them.

[rgleason]

See this translated page for Polauto - extensive information about recording polars.
Google Translate

Also this post about settings:
http://www.cruisersforum.com/forums/...ml#post1265072

[rgleason]

I also wish to point out this concept for arriving at good polars which is on Patrick's website:
Google Translate

Under "Super software Patrick:
There are a couple of decades, a project amateur hydrofoil was published in "the 2nd Australian Sailing Science Conference, Hobart, January 1999" a method of creating polar measured "for real." Their idea was to record everything in bulk without sorting or filtering (the memory of the PC was no longer a problem at this time) and then extracting the pole with a post-treatment. The advantage is that during the measurement was not to worry about the various settings of the data acquisition, filtering, etc ...
And they got a huge cloud of points. To get the fleece 10 kn wind for example, simply post-processing to remove all points with the above 10kn wind, but keep all those less than or equal to 10 kn.
The fleece is then the outer envelope of the cloud of points
The advantage is that the post-treatment points can be improved without the need to re-post the measure that is long and painful. There is no need to define a range of wind or angle, or speed boat. The measurement campaign may also extend over a large number of outputs, thousands of points "raw" accumulating in the file that will be post-processed. The "statistical smoothing" arrives at the final stage with the envelope of the cloud will eliminate all outliers, whatever the reason for the aberration.
It was very elegant as a process."




Incidentally, we see that the resolution of the measurement speed of the boat was only 1 kn, which affects considerably the accuracy of the measurements (points are aligned circles speed integers), but thanks to the smoothing interpolation of the casing is possible.

[kiwisails]

Thanks. I gave PCSails a shot. The science behind it is very involved after reading the white paper. I got the issues resolved and it working on Excel 2010. I then created the CSV file from the Endeavour 33 specifications. And come up with the Polars give me for say 12 kts TWS the following:

TWA/TWS 12kts 40 5.14 46 5.90 50 6.21 55 6.43 60 6.61 65 6.70 72 6.77 80 6.78 90 6.71 100 6.47 108 6.20 120 5.56 132 5.04 150 4.86 160 4.88 170 4.89 178 4.87
Ok but the calculated Boat speed after 150 TWA does not look correct. Ill re-read the PCSails manual and re-calculate. I am sure its something minor.

Anyway. Thanks for the assistance.

[maitai]

Originally Posted by sinbad7

maitai..

I am trying to create an optimized route using a stream .grib file (Current_gb_20121209.grib).

The map displays the arrows of the currents but I am unable to create a route from the Routings menu as I am unable to set the right departure date/time.

I have tried setting the departure as both 09/12/2012 00:30:00 UTC as shown at the top of the screen,and 12/09/2012 00:30:00 UTC without any luck.

Please advice what I am doing wrong..

Regards

Tore

Hi Tore,
You are trying to route far in the past, but that should be working.

You cannot route just with a currents-grib, you also need a winds-grib. Does your currents grib also contains Wind data, or did you also load a Wind-grib covering the same area AND period?

[rgleason]

Kiwisails, That is great that you've got it working. I'd be interested in your revised spreadsheet when you get it done. Also if you would, please upload your spreadsheet (add a .doc to the end or whatever) and your results with a description of how you did it and what the stumbling blocks were and solutions, to the PCsails thread? It would be much appreciated by all of us as we are learning too. Thank you!

[maitai]

Version 3.4.1 has been released.

Please note that qtVlm download site has moved to QtVlm Download

Apart from many small and not-so-small bug fixes, it mainly has:

-An improved routing module
-An option for calculating automatically several routing at different dates/hours, in order to find the best departure date/time
-An option to compare several routes
-An option for displaying day/night zones
-A new skinable dashboard (VLM mode only)
-Support for Sarana, RTOFS and COAMP grib files
-Grib color values are now configurable

And some other small improvements and additions....

[kiwisails]

RGL - here is the file rename and remove the doc. Just a few notes.

1. This was tested on Excel 2010
2. You MUST have the SOLVER add on installed.
3. It will come up with a CIRCULAR REFERENCE error. This is normal, and was intentional in the original sheet. Its in the manual
4. I also attached the whitepaper and manual saves others going digging again

I have not completed mine as yet, as I need some dimensions. Thanks

[rgleason]

Thanks KiwiSails,

After you get your set of Polars, you might want to improve them with real recorded conditions using Polauto.

Rick

[kiwisails]

RGL - One last thing - here is a much more detailed book on the Principles of Yachting Design which is where these Polar calculations stem from if you are interested.

https://www.dropbox.com/s/jlzju6corh...t%20design.pdf