I have often wondered about this. Can I as England with fleets in North Sea, Skag, Baltic convoy an army from Edinboro to Livonia.
Since you dont have East coast and West coast of Sweden, it must have water all around it. Does this mean you can pass a fleet from Skag to Baltic in one turn? It cannot be the same as going from Black Sea to the Aegean, but more like going from MAO to WMed. So in the same way you should be able to move fleets through, thus also convoys.
Clagr