Good assets and a nice idea. When giving an order to a ship, some kind of feedback that the command was received would be nice. The UI blocks you from seeing the ship reacting to the command. Additionally, a "job done!" sound would also help, since you might sail your ships all different ways and aren't seeing them all at once. For visibility and control, a list of your ships with either buttons to give quick commands or a button to jump camera to them would be nice. Very good start of a small game and with a little bit of polish would be a very enjoyable experience!