Polar diagram hiding in Garmin chartplotter?

[Sparx]

My Garmin chartplotter can graph apparent wind angle and wind speed. The plotter certainly sees boat speed. Is there a way to convert this data into a polar diagram, either on the chart plotter or to download this data. I can certainly manipulate the data into a polar using excel once it is on my laptop.

Any ideas?

[AnsleyS]

Sparx,


The question is whether you can get the NMEA 0183 or 2000 data from the wind instrument, the speedo and compass or the GPS(for boat speed and heading) to download to your computer for polar plotting. I have never seen a chartplotter with a polar diagram option.


The wiring of data to laptop is easy but what polar plotter program do you have?

[Sparx]

To date I have not dove into the whirling vortex of personal computer linked to boat systems. I suppose there are a number of things I could do with this....

I would appreciate a recommendation for a simple and sound method to connect PC to NEMA 2000 and for software for processing sailing polar diagrams. I had planned on simply plotting the data using polar coordinates, but I imagine there is software out there that is ready to do some of the lifting for me.

[Bill O]

Ansely hit it on the nail head and you must determine first if you have any type of NMEA out from your garmin chartplotter.
In opencpn, there is a plugin to make your own polar from the output data.

What boat do you have and does a polar form the manufacturer exist?

[Sparx]

The boat is a Maine Cat 38. There is not a polar diagram from the manufacturer. More importantly I am interested in developing am empirical polar from my own experience.

The Garmin MFD has two ports labeled "ethernet", plus a separate connection to the NEMA network. I am thinking this unused "ethernet" port might be interesting. The MFD also puts up a wifi network which I have used but not explored.

[SVHarmonie]

I am not a Garmin guy, and without knowing the model of your plotter it's impossible to say for sure... but...all modern charts plotters I am familiar with have a way of logging NMEA data to a file and saving it to the SD (or micro-SD) card, which can they be transferred by sneaker-net to a computer.

Once there, you can extract the data with Excel.

[Sparx]

Originally Posted by SVHarmonie

I am not a Garmin guy, and without knowing the model of your plotter it's impossible to say for sure... but...all modern charts plotters I am familiar with have a way of logging NMEA data to a file and saving it to the SD (or micro-SD) card, which can they be transferred by sneaker-net to a computer.

Once there, you can extract the data with Excel.

Sneaker net would be absolutely fine.

According to the Garmin manual waypoints, routes, tracks, and depth information can be saved to SD card. No mention of general NEMA data.

Tell me how this works on the plotters you are familiar with.

[Brewgyver]

Assuming all your transducers are "smart" all you need is a gateway to get NMEA data into your laptop. There are many on the market. If all your gear is NMEA 2000, just add a tee, and connect a spur (or drop) cable from the tee to whatever gateway you use. They're generally start at a couple hundred bucks US, or you can build one with a Raspberry Pi. Get (or build) a NMEA to wifi gateway and you're all set.

[Tupaia]

Originally Posted by Bill O

Ansely hit it on the nail head and you must determine first if you have any type of NMEA out from your garmin chartplotter.
In opencpn, there is a plugin to make your own polar from the output data.

What boat do you have and does a polar form the manufacturer exist?

I concur with Bill
Connect the Garmin up to a PC running OpenCPN and use the Polar Plug in. Start and stop recordings to correspond to different sail configurations (the plotter cannot know this).
You will end up with a set of Polars for different sail and sea conditions.

[Sparx]

Thanks for the thoughts.

Looks like the way to do this is adding a NEMA drop, then putting a NEMA to USB or NEMA to wifi gateway on, then loading OPEN CPN with the polar add in pulling data from the new gateway.

In other words, the information to build the polar diagram is not accessible through the Garmin system. But it is possible to build a parallel independent system that can do this.