Currently, any city which you can use to cross a river like Montreal on regular WW3 maps usually will have ports. However, these ports are nearly always useless as the which opens to the ocean will be blocked by another city, like quebec does to Montreal. It really limits your ability to build ships on countries like canada, or in countries like Poland or germany you cannot send ships to support cities downriver.
This might be intentional, but I think the devs should change it so that the cities are more like drawbridges that allow ships through, instead of land bridges that block them completely. This would completely change the game for the better, making large lakes like Lake Victoria, Great Lakes or the Caspian sea viable battlegrounds and making rivers like the Mississippi, nile, and yangtze key points of defense and attack, instead of mostly useless barriers that just make travel on land harder.
This might be intentional, but I think the devs should change it so that the cities are more like drawbridges that allow ships through, instead of land bridges that block them completely. This would completely change the game for the better, making large lakes like Lake Victoria, Great Lakes or the Caspian sea viable battlegrounds and making rivers like the Mississippi, nile, and yangtze key points of defense and attack, instead of mostly useless barriers that just make travel on land harder.