(a) A person enrolled in a mate training program approved by the Coast Guard, and who presents a letter or other documentary evidence that he or she is enrolled, may be issued an MMC rating endorsement as apprentice mate and may be signed on a vessel in this capacity. The rating endorsement as apprentice mate may be in addition to other endorsements; however, this endorsement does not authorize the holder to replace any of the regular required crew.

(b) Persons holding the endorsement as apprentice mate are deemed to be seamen.