Action cam 3-axis gimbals are not suited for water use. They are not effective in kite line mounts.
This is an interesting device from France that should be released in a few weeks: a action cam kite line mount with electronic stabilization;
During pole or kite use (water, snow, sand, ...) pole or lines point to the rider 100% of the time.
3D Gimballs are therefore overkill and what is needed is just an external level - 1 axis Gyro - computing the earth or sky line level with a brushless motor, therefore the name.
Looking like a digital camera, waterproofnest is obviously the key .....
No price or release date announced yet.