Seaman apprentice

Constructionman Apprentice
variation

Fireman Apprentice
variation

Airman Apprentice
variation

Seaman Apprentice
insignia

Collar
insignia

Seaman apprentice is the second lowest enlisted rate in the U.S. Navy, U.S. Coast Guard, and the U.S. Naval Sea Cadet Corps just above seaman recruit and below seaman; this rank was formerly known as seaman second class.

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Wikipedia