Section 47.630 - Restrictions(a) The mark (T) applies only to Great Lakes service from May 1 through September 30.(b) Notations are to be placed on the face of the load line certificate to the effect that: (1) The barge must be operated in compliance with the draft vs. cargo vertical center of gravity tables in the U.S. Coast Guard approved stability letter, and(2) The mark (T) is applicable only for Great Lakes service from May 1 through September 30 as per 46 CFR 45.9