Automatic creation of "cruising polars" using Signal K?

[flightlead404]

Hi

While daydreaming on a recent leg from Key Biscayne to Lake Worth and wondering why the real world is so far off the Predict Wind weather routing (lol) I came up with this.

Problem Statement: Official polars aren't available (or I can't find) for my '07 Hunter 38. Best I can find is Hunter 376 which is what I use but probably very different. But, even "official" polars are unlikely to be close as they are either theoretical or developed in ideal conditions with new boats, new sails, smooth hulls (marketing device?) etc. They don't reflect real world factors like my blown out sails, weight of my boat loaded for cruising, condition of my bottom, willingness to sacrifice a little boat speed for comfort, and of course the fact that when cruising I'm not constantly playing the controls to optimize the sails. More like a "check and tweak" every half hour or more.

Proposed Solution: Automated generation of polars from actual boat data collected from my instruments while actually under sail in the conditions I sail in, the boat set up how I sail it, reflecting my personal choices in operation, condition of the boat etc.

With the Pi and PiCAN hat I can pull everything off the SeaTalk/NMEA2k data buss including wind speed, wind direction, boat heading, boat speed, GPS course and speed to automatically develop polars.

I could even use a line off the alt field to raise a GPIO pin on the Pi to stop data collection when the engine is running.

Before I start down this road, has anyone done this already? What problems do you foresee?

[Bill O]

Opencpn already has a polar plugin. https://opencpn.org/wiki/dokuwiki/do...:sailing:polar

[flightlead404]

Originally Posted by Bill O

Opencpn already has a polar plugin. https://opencpn.org/wiki/dokuwiki/do...:sailing:polar

Excellent, someone else has already done the hard work