Hello fxmodels,
Yes indeed, there are AI ships in freeroam but you need to select "Toggle ships on/off" when you select the start position of your ship. Please have a look at Traddle's picture in this topic (http://80.95.161.114/shipsim/forum/index.php/topic,26362.0.html).
Eventually, you could use the mission editor to enhance the number of AI ships moving around in a harbour, but obviously it would be less straightforward.
Regards,
Luc