Editorial Note on Part 157
Editorial Note: Nomenclature changes to part 157 appear by USCG-2008-0179, 73 FR 35015, June 19, 2008.

§ 157.10b Segregated ballast tanks, dedicated clean ballast tanks, and special ballast arrangements for tank vessels transporting Outer Continental Shelf oil. ( a ) Each tank vessel that is engaged in the transfer of crude oil from an offshore oil exploitation or production facility on the Outer Continental Shelf of the United States on or after June 1, 1980 must, if segregated ballast tanks or dedicated clean ballast tanks are not required under § 157.09, § 157.10 or § 157.10a, have one of the following: ( 1 ) Segregated ballast tanks with a total capacity to meet the draft and trim requirements in paragraph (b) of this section.
( 2 ) Dedicated clean ballast tanks having a total capacity to meet the draft and trim requirements in paragraph (b) of this section and meeting the design and equipment requirements under subpart E of this part.
( 3 ) Special ballast arrangements acceptable to the Coast Guard.
( b ) In any ballast condition during any part of a voyage, including that of lightweight with either segregated ballast in segregated ballast tanks or clean ballast in dedicated clean ballast tanks, each vessel under paragraph (a)(1) or (a)(2) of this section must have the capability of meeting each of the following: ( 1 ) The molded draft amidship (dm), in meters, without taking into account vessel deformation, must not be less than “dm” in the following mathematical relationship: dm = 2.00 + 0.020L for vessels of 150 meters or more in length dm = 1.25 + 0.025L for vessels less than 150 meters in length
( 2 ) The drafts, in meters, at the forward and after perpendiculars must correspond to those determined by the draft amidship under paragraph (b)(1) of this section, in association with a trim, in meters, by the stern (t) of no more than “t” in the following mathematical relationship: t = 0.015L for vessels of 150 meters or more in length t = 1.5 + 0.005L for vessels less than 150 meters in length
( 3 ) The minimum draft at the after perpendicular is that which is necessary to obtain full immersion of the propeller.
( c ) Special ballast arrangements are accepted under the procedures in paragraph (d) of this section if: ( 1 ) The vessel is dedicated to one specific route;
( 2 ) Each offshore transfer facility on the route is less than 50 miles from shore;
( 3 ) The duration of the ballast voyage is less than 10 hours;
( 4 ) They prevent the mixing of ballast water and oil; and
( 5 ) They provide suitable draft and trim to allow for the safe navigation of the vessel on the intended route.
( d ) The owner or operator of a vessel that meets paragraph (c) of this section must apply for acceptance of the special ballast arrangement, in writing, to the Officer in Charge, Marine Inspection, of the zone in which the vessel operates. The application must contain: ( 1 ) The specific route on which the vessel would operate;
( 2 ) The type of ballast to be carried;
( 3 ) The location of the ballast on the vessel;
( 4 ) Calculations of draft and trim for maximum ballast conditions; and
( 5 ) The associated operating requirements or limitations necessary to ensure safe navigation of the vessel. Note:
Operating requirements or limitations necessary to ensure safe navigation of the vessel could include (but are not limited to) weather conditions under which the vessel would not operate and weather conditions under which cargo would be carried in certain cargo tanks on the ballast voyage.
( e ) The Coast Guard will inform each applicant for special ballast arrangements under paragraph (d) of this section whether or not the arrangements are accepted. If they are not accepted, the reasons why they are not accepted will be stated.
( f ) Each tank vessel under this section may be designed to carry ballast water in cargo tanks, as allowed under § 157.35.
[CGD 79-152, 45 FR 82249, Dec. 15, 1980]