segler said..
Very nice video. What camera did you use, and what software did you use to display the overlay gauges?
Cheers.

Sony HDR-AS300 action cam with waterproof housing. Attached to the side of my windsurfing helmet.

I don't think the Sony action cams are still in production unfortunately. They seem to have given up again the competition from GoPro, which is a shame because only a few years ago they were ahead of GoPro in many ways. The advantage for me of this cam is that they are a better shape to attach to the side of a helmet looking forward - GoPros stick out the side far too much. The disadvantages are only 1080 resolution (in this particular model) and somewhat less effective image stabilising compared with the latest, (Hero Black 8 and later) superb GoPro stabilisation.
This Sony cam has a built in GPS which produces a data file that is compatible with the program I use:
Telemetry Overlay (for mac).
Telemetry Overly is very easy to use and very adaptable to different sports. Not outrageously expensive either. I like it.
goprotelemetryextractor.com/telemetry-overlay-gps-video-sensorsThere was also a Sony HDR-50 action cam which I also have. The disadvantage of it is that it does not have the inbuilt GPS, but this also enables the battery to record for longer, up to 2 hrs, whereas I only get about 1.5 hrs from the HDR-300.
There is also a FDR-X3000 4K Action Cam, that seems to have all the features of the HDR-300 but also does 4K recording. Not sure if that one is still in production?
But, given that the Sony are now out of production, the new GoPros are probably the better option, even if they are not as well packaged for helmet side mount. (I recommend you
don't mount your cameras on the
top of your helmets, as you can then very easily push a hole on your sail)