I can see the sense in that, but it is annoying when that last pesky surviving Dromon in the English Channel stops me re-inforcing my armies in the Med...

The other question I have is what do you have to do to make a sea 'friendly' - I can only ever remember them being either blockaded or neutral, even late in the game when I pretty much own the whole map and there are very few AI ships? Or have I just not been paying proper attention?