Credential means any or all of the following:
Merchant mariner credential or MMC means the credential issued by the Coast Guard under 46 CFR part 10 . It combines the individual merchant mariner's document, license, and certificate of registry enumerated in 46 U.S.C. subtitle II part E as well as the STCW endorsement into a single credential that serves as the mariner's qualification document, certificate of identification, and certificate of service.
46 C.F.R. §5.40