I like the premise. Here's my thoughts:
- Add vision cones or some kind of indication on the sides of the ship so I know when ships are in range and will get hit by my shots.
- The waves often blocked my shots, but it was difficult to know when that was going to happen as it was near impossible to judge their elevation. So I had no idea when they were intersecting my line of fire.
- I'm not sure how much of an issue this might become, but it looks to me like the LODs of the ships don't seem to change no matter how close or far away the camera is. It's not currently as issue as everything is fairly low poly, but might become a problem later down the line.
- Maybe add some random islands to avoid (Or even some with treasure) and some friendly units who can join up with you and double up your firepower, trade with, or one-sidedly attack.