46 CFR § 153.470 - System for discharge of NLS residue to the sea: Categories A, B, C, and D.
Unless waived under § 153.491, each ship that discharges Category A, B, or C NLS residue, or Category D NLS residue not diluted to 1/10th of its original concentration, into the sea under §§ 153.1126 and 153.1128 must have an NLS residue discharge system meeting the following:
(a) Minimum diameter of an NLS residue discharge outlet. The outlet of each NLS residue discharge system must have a diameter at least as great as that given by the following formula:
(b) Location of an NLS residue discharge outlet. Each NLS residue discharge outlet must be located -
(1) At the turn of the bilge beneath the cargo area; and
(2) Where the discharge from the outlet is not drawn into the ship's seawater intakes.
(c) Location of dual NLS residue discharge outlets. If the value of 6.45 for K is used in § 153.1126(b)(2), the NLS residue discharge system must have two outlets located on opposite sides of the ship.