Yes, building a proper dock is a pest. Not only you put your hammer away as soon as your chest gets wet, you also have no free camera to properly to align the building parts. Because of these two points you cannot build walls from the sea floor up. Swimming is wonky... you can swim at the bottom of stairs and drown because you can't swim onto the first step. There are no gates that come in ship sizes. And the AI is cheating you because monsters don't use stamina. So even if your moat was two miles long, they still would swim around to attack your boat docked on the other side. And what good is a moat if the large waves on storms right pass THROUGH it? You simply cannot build quiet protected harbors surrounded by proper sea walls, moats and access gates.