According to the U.S. Department of Defense, enlisted sailors in the U.S. Navy are referred to by the term "rate," rather than "rank," based on their pay grades E-1 to E-9. Enlisted sailor rates range from Seaman Recruit to the highest-level Master Chief Petty Officer of the Navy.
Enlisted sailor rates for pay grades E-1 to E-4, in order, are Seaman Recruit, Seaman Apprentice, Seaman and Petty Officer Third Class. Petty Officer Second Class, Petty Officer First Class and Chief Petty Officer, known as non-commissioned officers, are considered mid-level with pay grades E-5 to E-7. Senior-level non-commissioned officers include Senior Chief Petty Officer, Master Chief Petty Officer and Master Chief Petty Officer of the Navy.
Personnel designations for pay grades E-1 to E-3 combine a sailor's pay grade with a sailor's job specialty, known as his "rating." Rating categories include administration, aviation, construction, dental, engineering, hull, medical or weapons, according to BlueJacket.com. For example, personnel at the E-1 level include Seaman Recruit, Hospitalman Recruit, Airman Recruit, Fireman Recruit, and Constructionman Recruit.
The U.S. Department of Defense reports that sailors with pay grades E-1 to E-4 are considered to be in their core-skill training phase or on their first assignment. Mid-level service members have increased duties and responsibilities depending on their occupational group, which may include supervisory duties. Senior-level rates have been on active duty for 15 to 30 years. Promotion to the Master Chief Petty Officer and Master Chief Petty Officer of the Navy positions, both at the E-9 pay grade, are based on a board selection process.