Section 157.228 - Isolating Valves: Closed during a voyage(a) The master of each U.S. tank vessel under § 157.10a(b) , § 157.10a(c)(2) , § 157.10b(a)(2) , or § 157.10c(c)(2) shall ensure that the valves under § 157.222(d) remain closed during each voyage.(b) The master of each foreign tank vessel meeting § 157.10a(b) , § 157.10a(c)(2) , § 157.10b(a)(2) , or § 157.10c(c)(2) shall ensure that the valves under § 157.222(d) remain closed when the vessel is on a voyage in the navigable waters of the United States.CGD 82-28, 50 FR 11629, Mar. 22, 1985