Does anyone know of any web sites or apps that can analyse a GPS track and determine things like waves caught, speed, tacks/gybes etc? I have looked and there's a couple of very basic ones but nothing with any kind of detailed analysis.

I have tried various surfing and sailing apps on smart watches to track sessions. They're all pretty crap. They suffer from the fundamental problem of being locked in to the developer's assumptions about what is happening.They use all sorts of predefined parameters for detecting waves caught and tacks and gybes and all the rest and try to do it in real time.

When I'm out on the water I am too busy to look at a watch to see what has been happening, and the conditions and gear often mean that the way I am riding is very different from other session.

I think it would make more sense to load a GPS track into an app then tweak all the parameters to extract the information. Many GPS apps or smart watch can export a GPX file that contains all the data.

- gybes/tacks determined by speed and direction changes. Similar rules could detect waves caught.
- average speeds over n seconds
- average speeds within bounds to filter out peaks and troughs and lulls and glitches