PCSail - Excel sheet to make VPP for Sailing yachts

[JesperWe]

Originally Posted by tiersp

Hello,
I have post an english version of Polauto on the french forum
It's the thread give by Kiltym above.

Oui, mais comment voulez-vous les textes?
Il suffit de regarder le logiciel et d'écrire la traduction dans un mail?
Il ya de bons outils disponibles pour faire une traduction d'un logiciel en plusieurs langues, vous savez!

[rgleason]

Jesper, your boat deserves some polars! -BTW Are you near Tromso?

[JesperWe]

Originally Posted by rgleason

Jesper, your boat deserves some polars! -BTW Are you near Tromso?

??? No almost as far from Tromso as I can get on this planet.

[rgleason]

...used google translate. ...there are so many French skills for sailing

Je vous remercie pour vos Maitai 2 poteaux et Tiersp pour y adhérer. Description Maitai sonne idéal. En effet, je suis langue contestée, et une version anglaise, il serait beaucoup plus facile pour moi. Merci pour la suggestion JesperWe traduction GNU, c'est peut-être l'outil Polar, nous pourrions tous utiliser!
- Commencez avec une VPP de Polar Sailfish ou PCsail.xls pour générer un ensemble de départ de polaires et ensuite utiliser Polauto de l'affiner sur le bateau dans des conditions réelles.

-Faut-il faire runs prévus avec aucun changement dans (Bien sûr, voiles, etc) et dans des conditions sans marée?

PS Je vais regarder la version traduite du forum Polauto aussi, et peut-être essayer quelques-uns lycée français d'il ya longtemps ....

...used google translate. ...there are so many French skills for sailing

[rgleason]

NavMonPC Yahoo user group.

From Rick To: NavMonPc@yahoogroups.com
Subject: [NavMonPc] Polar Tables

I'd like to improve some polar tables created by Sailfish, with a nmea data stream that would be recorded, then selected and filtered for various conditions (sea state, sail used, etc). It would be nice to be able to make comments, and to stop and start the data logging, and finally to filter out 'out of range' points and select which nmea data.

This sounds like a big request, ...NavMonPC appropriate software for that purpose? It looks like it does logging!

RE: [NavMonPc] Polar Tables
FROM: Max Lynn TO: NavMonPc@yahoogroups.com Monday, October 1, 2012 3:20 PM

Rick,

I don't know how long you have been monitoring the group, but we have had some previous discussion of the problem you are working. I have played around with that issue, and have tried the following.

First, I log both NMEA and CSV file formats. Using the CSV format in Excel, I isolate certain time segments of a race that I wish to process by plotting the boat speed, TWS, and TWA variables and marking the times of interest.

I then go into the NMEA log file and strip the data from that area into a separate file.

I then play the segment through NavMonPC's playback capability to an iPad app called iRegatta via an ad hoc network.

IRegatta constructs a polar file(table) in CSV format.

Obviously all this is tedious, but unless you have very long race segments, I don't see any method other than manual editing such as I have described that would yield useable data. If you have only short day races with multiple tacks and jibes, all the data during (and shortly after) those tacks and jibes needs to be filtered out. Much of that filtering requires a judgment call with respect to the time period to be rejected.

If you are fortunate and have long races, then the method I've described becomes much easier, assuming there isn't a great deal of course changes. But it still requires manual editing unless you can stop and start the data logs at opportune times. I couldn't do that and sail the boat as well.

Of course, to get good results from all of this requires well calibrated instruments, attention to the variability of sea conditions, sail trim, etc., etc. You can learn from this exercise, but it requires a lot of work.

[rgleason]

Extemporaneous notes while installing and using Polaires Auto without Nmea, looks like it might be a solution, with a few improvements to the interface. See attachment.

[rgleason]

Written to Tiersp - Patrick, Polaires Auto RE a hand entered polar.

Patrick, While trying Polaire Auto, in one instance the polar did not seem to work. I hope I can upload the screen snapshot jpg of the polar. The puzzling thing is in the grid at 8nds data is entered from 72 degrees to 144 degress, however the polar chart shows entries all the way to 180 degrees. I tried refresh of the screen, and I don't know which file is being used so I can't upload it. Perhaps there is a simple explanation. Thanks

[rgleason]

Subject: [NavMonPc] Polar Tables - Additional information regarding filtering from Paul, who is the author I believe.

Hi Rick, NavMonPc does have filtering, but it doesn't modify the raw NMEA data being recorded to the logfile. The programmable filtering does smooth the data being recorded to the "spreadsheet log", and you can enter notes in this log as well. The spreadsheet log is saved as a tab-delimited textfile, and the logging interval can be as short as one second, so this could be used as an input for a polar-creation program.

The filtering is simple low-pass filtering for the individual parameters, and is really only useful for reducing the random noise in the raw data. For polar creation you would want to have filtering that takes into account multiple factors, allowing you to automatically discard the data being recorded during changes in course / speed / wind, etc. This could be done in a second post-processing pass on the spreadsheet file by another program.

I'm out of the country now (which is why I've not been replying to the group), but will be back later this week. Regards, Paul

[rgleason]

How to install NavMonPC with virtual ports on a Win7x64
Yahoo! Groups

[rgleason]

Some recent emails from navmonpc on yahoo groups:

Thank you Paul, that information is very helpful. Also Max I appreciate your experience.Has anyone tried getting good polars while sailing? Is this possible or is it too much distraction so that you cannot in practicality do it? I am looking for good techniques to do it. I assume the post processing could be done afterwards, with taking timely notes when there are changes, sea state and sails, with the nmea data continuously recording.

A french Polars Forum and software indicates the normal data taken is True Wind and Speed from the Boat Transducer, and if you want VMG you need to have Apparent as well. I am still wondering about how to cancel the effect of current, as I have seen what it does to my tracks on GPS! Thank you for your help. Rick

mikeleslie4242 on NavMonPc@yahoogroups.com
I also live in area with a lot of current, and i've tried getting good polar data while sailing. If you're doing a ergatta, you night get OK data for targets, but certianly not a full polar plot. do enough Short course w/l races during the day and you can generally find a couple of good legs. I carefully look over the logs and find the best segments to use. Last time I did this i got 8 minutes of good data which gave me a total of 6 data points. By contrast, we went out for a test sail in an area of no current and in 3 hours were able to generate full plots for 3 wind speeds. It was erll worth the effort. Current can have a huge affect on boatspeed(obvious) and AWA (more subtle) both have so large an effect on polars that the data isn't very useful (ok, you'll be within 1/2 knot and 4 degrees TWA) but you can probably guess better numbers than that.
The other thing about wind angle data in current is that, depending on the insturment system, your AWA displayed may not be the same as what's being measured. B&G in particular back calculates the displayed AWA from TWA to accomidate for heel, upwash and current depending on model) Ockam, Racing Bravo, NKE and some others just display the masthead reading.
Simple answer: go for a fully crewed test sail in as little current as possible and test various angles and windspeeds. You'll be glad you did. If not, buy the data from your favorite provider, I've found them to be pretty good.

From Tim Tupham Navmonpc yahoogroups
Hi, I've done quite a bit of work on this area for all sorts of boats from America's Cup to Volvo boats, and the following comments may be useful:
- current is only significant if you make the mistake of using GPS data for heading or boat speed (apart from a possible 2ndary effect on sea state). If you use boat speed and compass heading together with wind data, then everything is in the same frame of reference and the current has no effect
- you should always use TWA and TWS, not apparent. For use on board for target speeds and sail trim you will probably want the TWA to be measured with respect to the boat's centerline, as this eliminates the problem of measuring leeway, whereas yacht designers and weather routing software will prefer TWA with respect to the boat's track through the water (i.e. compass heading + leeway) as this takes leeway into account when assessing performance or deciding on the optimal route.
- whenever possible do the data collection on a test sail rather than on the race course, as you can just concentrate on speed, and sail at the full range of wind angles, without all the other pressures of racing Tim

[rgleason]

Simple Vector Representation of Nmea Data. See PDF of spreadsheet at bottom.

http://www.cruisersforum.com/forums/...ml#post1067393

[rgleason]

POLAUTO version 4.2 update availaable (for WindowsXP, Vista and 7)
Patrick (Tiersp on the OpenCpn Forum) has made some great improvements to PolAuto and I am sure you will find this to be a very useful tool for creating Polars for your boat, from actual sailing runs using an active Nmea0183 data stream on COM Port (or by playing recorded data through NavMonPC or OpenCpn). The program has many utilities such as import and export to different formats, data source selection, nmea0183 filters and % averaging of new data with old data points. Download "instalpolautov4_2.exe" under Feb 9, 20133

Polaires Auto - English Translation - main page

Polaires Auto Forum - English Translation -

[rgleason]

Here's the English version of Polaires Auto 4.2 Polaires auto

[rgleason]

Patrick [Tiersp] has been busy see this post for new links and
updated Polauto version 4.3.2 for creating polars.

[rgleason]

From Polauto website - Thank you Patrick [Tiersp] Very helpful showing the vectors in play.

The data used by "Polauto"

• The instruments measure:
  • For the boat:
    • GPS:
      • SOG SOG Vf
      • COG: Vector Angle Vf with respect to the axis of the vessel (0 to 360 °)
    • The speedo:
      • VHW: Water speed Vs
    • The compass:
      • HDG: the angle of the velocity vector surface relative to magnetic north.
  • For the wind
    • The anemovane:
      • VWR the apparent wind angle of the vector Va in relation to the axis of the vessel and its intensity.
      • MWV, the angle of the apparent wind vector Va with respect to the axis of the vessel and its intensity
      • Example of NMEA sentence: $ IIMWV, 301, R, 09.07, N, A * 1F
        • 301 is the angle, R indicates that it is the relative wind, 7.9 is the wind speed in knots, or the angle of the wind vector Vv true in relation to the axis of the vessel and its intensity if the wind is interfaced with the speedo.
      • Example of NMEA sentence: $ IIMWV, 116, T, 11.7, N, A * 14
        • 116 is the angle, T indicates that this is the true wind (True), 11.7 is the wind speed or the angle of the wind vector Vr real relation to the axis of the boat and its intensity if the wind is interfaced with the gps.