What is the navigable part of a river, bay, etc., through which vessels enter or depart; the part of a harbor or channel ehich is kept open and unobstructed for the passage of vessels. Totten. the rough called?

fairway — The navigable part of a river, bay, etc., through which vessels enter or depart; the part of a harbor or channel ehich is kept open and unobstructed for the passage of vessels. Totten. the rough. (Webster's 1913.)