Wear os

Here is my own individual comment about this.

What REALLY matters is whether the watch has built-in GPS. Not "connected GPS" which requires a phone nearby. It must be built-in.

If the 5 atm watch has built-in GPS, just run the watch with the GPS turned on. Then upload whatever file it produces to something like Strava, and you will get a track map, speed, maximum speed, and distance in the Strava report.

Most watches with GPS produce .fit, .gpx, or .nmea files. Strava accepts all these.

Note, you might need to upload the file to a computer first if Strava cannot upload directly. No biggie if the watch acts like a usb mass storage device to the computer. Most do.

My Timex Ironman GPS watch is not a sailing watch, but I use it with Strava as described above. It is a great way to archive my sessions.

Other fitness sites, like Endomondo or Runkeeper or others, work this way, too.

Strava, for example, IS a speed app. Also mapped track, maximum speed, average speed, distance, session time, moving time, and other info. I have been using the free version for years. Other fitness apps do all this, too, for free. Most of them, however, are for running or biking, but they show windsurfing information just fine. I archive my sessions in the Strava cloud.

Windsport Tracker does have the ability to import .gpx files. If your watch exports only .fit, you can convert .fit to .gpx using GPSBabel. Strava imports .fit directly.