(a) Each hopper dredge assigned a working freeboard may be operated at drafts from the normal freeboard to the working freeboard if the—

(1) Seas are not more than 10 feet;

(2) Winds are not more than 35 knots;

(3) Area of operation is not more than 20 nautical miles (37 kilometers) from the mouth of a harbor of safe refuge; and

(4) Specific gravity of the spoil carried is not more than the highest specific gravity of spoil used in the stability calculations required by subchapter S of this chapter.

(b) The Assigning Authority designates on the face of the dredge's load line certificate—

(1) Each restriction contained in paragraph (a)(1) through (a)(3) of this section; and

(2) The maximum specific gravity of the spoils allowed to be carried.