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. Wikipedia

Seaman recruit is the lowest enlisted rate in the United States Navy, U.S. Coast Guard, and the U.S. Naval Sea Cadet Corps just below seaman apprentice; this rank was formerly known as seaman third class. Two separate pay grades exist within this rank — one for those with service of less than four months, with a higher pay scale for those in service for more than four months, even if they have not yet advanced to seaman apprentice. Wikipedia

A U.S. Navy and Coast Guard rank Wikipedia Disambiguation