I think I've encountered 1 player who was blatantly cheating since I started this game (been playing for the last 16 months consistently).
I was attempting to tuck a FoTD...was tucked on a random rock beneath the water line, and the kid consistently sniped me from his ship no matter where I moved to. Deduced he was probably using hit-box hacks.
I don't think I've ever encountered someone using 'aim-bot'.
However, I have encountered players who can double-gun me almost as soon as I step foot on their ship, but I'm aware that that is probably just skill, not hacks.
If you think you are encountering aim-bot hackers, I would ask that you really analyze their movements. Seasoned PvPers have a special way that they move around. The can sprint through the lower portion of a ship without getting caught on anything, sprint jump along the railing of the upper deck, and do a number of other interesting maneuvers while fighting. If a player is doing all of this while also never missing a shot, they aren't hacking, they've just practiced a lot.
Now if you are fighting a pirate who just chases you around in a circle and suspiciously always has his head locked to the center of your chest, that could possibly be aim-bot.
My guess though is that you've been encountering a lot of the first pirates I've described, in which case those players are not hacking, they've just spent more time practicing than you have.