Any cheap drones on the market that can follow and work for windsurfing.
Whats worth looking at.
Someone more knowledgeable can chip in with some other models...
But so far I have found the smaller, cheaper drones just aren't FAST enough to keep up with windsurfing. For example the DJI Spark has a good tracking function which works nicely walking or running but it can't follow me on the board it just isn't up to speed. I was very impressed with the tracking software though on this cheap model, so I imagine the bigger DJI's (and newer ones) are even better.
thanks sean.
nice and cheap.
might be a good option for light wind days. dji website says 50km/hr max speed in no wind.
You might check looming regulations. There is proposed a size limit below which they're not regulated. If you get a big one you will need a permit and you'll have more rules to follow.
Don't rely on the follow function, you want someone in control with an eagle eye on the battery level, flying back against the wind chews lots more juice.
Find a mate with a Phantom 4, best option 
Phantom 4 is the smallest you can go really.
my mate had a maverick and in strong winds nearly lost it. it couldn't get back to base!!
but...when I was riding 8.6 and 135 L board in 15 knots it was happy.
What Paul said. I'd ad to that the DJI Phantom 3.
from my experience both the Mavic 2 and Phantom 4 will fly in 35 knots no problem.
That said you will need to know what your doing.
whenever i have my drone up everyone seems to think that you can set them up to follow people
All thanks to this misleading video (which was all a total scam) but had everyone excited.
they took $34 million dollars from 60, 00 customers and delivered nothing but wasted time and unrealistic expectations of how easy drones are to operate.
www.theverge.com/2017/1/12/14248988/lily-drone-tracking-dead-refunds
Stehsegler is spot on although it should be noted that the Phantom 4 gimbal is less able to withstand heavy maneuvering than the mavic 2s. Resulting in a camera wobble and pause on the p4 - usually just as a rider is doing their biggest move of their life.
I always seem to get some clown telling me that their $150 drone flies great and can do HD video - but its never the case.
The DJI Mavic does a reasonably job at following. Should be reasonably cheap by now.
But it is a bit hit and miss, esp when its windy.
Did manage to get this footage, but also a lot of empty ocean shots.
It's in auto follow mode with the controller still on the beach
