157.160—Tanks: Ballasting and crude oil washing.
(2)
For oil cargo residue control, at least 25 percent of the cargo tanks are crude oil washed before each ballast voyage and that each cargo tank is crude oil washed at least once every fourth time crude oil is discharged from the tank, but no tank need be crude oil washed more than once during each 120 day period;
(3)
Ballast water in a cargo tank that is crude oil washed but not water rinsed during or after the most recent discharge of crude oil from that tank is discharged in accordance with § 157.37(a); and
(b)
The owner, operator, and master of a tank vessel having a COW system under § 157.10a(a)(2) or § 157.10c(b)(2) shall ensure that—
(1)
Ballast water is carried only in a cargo tank that is crude oil washed during or after the most recent discharge of crude oil from that tank;
(2)
Before each ballast voyage a sufficient number of cargo tanks have been crude oil washed during or after the most recent discharge of crude oil from those tanks to allow ballast water to be carried in cargo tanks:
(3)
For oil cargo residue control, at least 25 percent of the cargo tanks not used for carrying ballast water under paragraph (b)(2)(i) of this section are crude oil washed before each ballast voyage, and that each cargo tank is crude oil washed at least once every fourth time crude oil is discharged from the tank, but no tank need be crude oil washed more than once during each 120 day period;
(5)
Ballast water in a cargo tank that is crude oil washed but not water rinsed during or after the most recent discharge of crude oil from that tank is discharged in accordance with § 157.37(a).