Section 156.400 - Applicability(a) This subpart applies to oil tankers engaged in the ship-to-ship transfer of oil cargo between oil tankers (STS Operations), and to their STS Operations conducted on or after April 1, 2012, when at least one of the oil tankers is of 150 gross tonnage and above. These rules are in addition to the rules of subpart A of this part, as well as the rules in the applicable sections of parts 151, 153, 155, 156, and 157 of this chapter.(b) This subpart does not apply to STS Operations-(1) If the oil cargo is intended only for use as a fuel or lubricant aboard the receiving vessel (bunker operations);(2) When at least one of the ships involved in the oil transfer operation is a warship or a naval auxiliary or other ship owned or operated by a nation and used, at the time of the transfer, in government noncommercial service only; or(3) When the STS Operations are necessary for the purpose of securing the safety of a ship or saving life at sea, or for combating specific pollution incidents in order to minimize the damage from pollution; except that such vessels are subject to the requirements of §§ 156.415(g) and 156.420 .