Tug Boat simulator

humm...interesting choice of game..I only found this browsing around Steam, not sure if a tugboat model is available though.

http://www.shipsim.com/

http://store.steampowered.com/app/48800/

Is there a decent tug boat simulator? Or a decent ship simulator with a tug boat available? If so, what's it called?d-rtyboy

ship simulator extreme?