(3) For the purposes of these Regulations, every reference to “the Port of Churchill” is a reference to “all the navigable waters, including any foreshore, commencing at the northern extremity of Eskimo Point and running on a course due north to a point distant five nautical miles from the northernmost extremity of Eskimo Point; thence, on the circumference of a circle with the said northernmost extremity as a centre, easterly and southerly to the shore of Hudson Bay at the high-water mark; thence, following the said high-water mark westerly to Cape Merry; thence, following the high-water mark on the eastern shore of the Churchill River upstream as far as the tide ebbs and flows; thence, across the Churchill River to its western shore; thence, northerly and following the high-water mark downstream to the point at Old Fort Prince of Wales and across to Eskimo Point and to the place of beginning”.