The Upper Patapsco River area, with its corresponding speed limit, is set forth in §B of this regulation. Middle Branch encompasses the area upstream of a line beginning at, Harbor Hospital at or near Lat. 39° 15.003’ N., Long. 76° 36.702’ W., then running 11° (True) to Ferry Point, at or near Lat. 39° 15.357’ N., Long. 76° 36.610’ W., and running to the head of the branch. This area has a 6-knot speed limit all year.