According to the screen shot below; I traveled from my Lord's city "city 2 (648/848)" (which is in a closed contour) to My city "city of mr.innocent 2" (648/844) (outside the contour) in less than 15 minutes!!! {I have Only 1 hero with Novice Logistic skill}

I think this is a BUG, where a closed water contour is NOT taken into account, while traveling to and from a city within a closed contour to one outside of it.