46 C.F.R. § 11.514
(a) The minimum service required to qualify an applicant for endorsement as Second Assistant Engineer of steam, motor, and/or gas turbine-propelled vessels is—
(2) One year of service while holding an MMC endorsement as Third Assistant Engineer, which includes—
[USCG-2004-17914, 78 FR 77909, Dec. 24, 2013, as amended by USCG-2021-0097, 89 FR 93093, Nov. 25, 2024; USCG-2021-0834, 89 FR 102336, Dec. 17, 2024]