This is a rather subtle, but very important and fundamental mechanic of the game. When you are playing the game, you will notice that if you turn your ship (especially at very slow speeds this is noticeable), it turns using the center as an axis. If you don't know what that means, well effectively it means that instead of turning like a real ship would, it magically "spins" the fore and aft end around when it would make no physical sense, like the ship has rockets on the sides or something.
This is a pretty big problem; not only is it not realistic, it creates frustrating behavior when you're trying to make tight maneuvers around islands (sometimes your aft end might hit a shore and cause you to get stuck when it shouldn't) and it allows players to dodge torpedoes in physically impossible and frustrating ways. I always get frustrated when I shoot torpedoes at someone and any normal person (or I suppose a new player not familiar with the center axis of rotation) would expect my shot to land in their aft end, but they magically swing their aft end around and the torpedoes pass by harmlessly.
The game already has made a step in the right direction by not allowing you to turn when stopped, but the center axis of rotation is extremely bizarre and would even suggest the ability to turn while stopped, if a ship could actually rotate this way in real life. I feel that it is very out of place in this game.
EDIT: I thought of a better analogy for those who don't get it... imagine a helicopter, hovering and spinning in place. That is how our ships turn right now, with the exception that they have to be moving forward or backward first. It's strange.