Quote Originally Posted by chemchok
I might be totally wrong on this, but I think that most sea travel followed the coasts of the Mediterranean during the time period.
I recall seeing a Scientific American recently where Bob Ballard (of Titanic fame, the undersea version, not the James Cameron version) found the wreck of a Phoenician vessel in the middle (out of sight of coastline) of the Mediterranean. There was evidence (empty wine casks) that indicated that it was plying a well-used trade route when it sunk. This would have pre-dated Rome by several hundred years at least. That's not to say the Romans had the same technologies or sailing savvy though, I'm not sure about that.

Quote Originally Posted by chemchok
On the campaign map the trade routes follow the coasts, navies get longer movement points if they follow coastal paths; it just seems to reflect coastal travel in general.
I have noticed that moving along coastlines gives more movement points, but recently when I was sailing a navy from the North of the Black Sea to the northern coast of Asia Minor, the green blotch of possible movement had a finger which followed the trade route from Campus Scythia to the port of the city to the south (forgot the name, sorry). Maybe it was an isolated thing, but I have noticed it in other places as well. Perhaps it has to do with depth?