Area. All of the waters upstream of a line beginning at a point at or near Lat. 38° 39.680' N., Long. 75° 47.815' W., then running 147° True to a point at or near Lat. 38° 39.653' N., Long. 75° 47.793' W. The speed limit for the area described in §A of this regulation is 6 knots all year.