Reach said..
Anyway, keep those big manly chests puffed up if it makes you feel good.

It's not about that (at least with me), as I explained, on two levels. And sorry I have embarrassed you about the EM. That was not intended either. So all I can add is, post about this idea. The windsurfing and SUP sections would be good sections to post, since they get used. It might get traction ?. If it doesn't, the oh well. But there are some very clever people on here from all walks of life. With a bit of input, it might take off ?

Another angle, if no interest here, is austech forums . Proper techs and engineers (retired) haunt this site. They are very brainy people, backed with decades of design and manufacturing experience. Many don't surf (some of them are in wheel chairs !), but would take an delighted interest in a novel project like this, and would definitely help you with the electronics aspects.

I've only ever seen two sharks in Adelaide. I've been sailing nearly 20 years now. We have spots in SA that are very sharkey. I would not sail there. If you handed me an electronic device, I still would not sail there. But, there are plenty of spots in SA that are low risk. So, I sail those spots.