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Navy Enlisted Job Descriptions & Qualifications
Machinist Mate (Advanced Technical Field) MM
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General Info: Machinist's mates operate and maintain steam turbines and reduction gears used for ship propulsion and auxiliary machinery such as turbogenerators, pumps and oil purifiers. They also maintain auxiliary machinery outside of main machinery spaces, such as electrohydraulic steering engines and elevators, refrigeration plants, air conditioning systems and desalinization plants. They may also operate and maintain compressed gas producing plants.

What They Do: The duties performed by MMs include: aligning piping systems for oil, water, air and steam, and controlling the operation of ship boilers and steam turbines used for ship propulsion and service systems; controlling operation of turbogenerators used to produce electrical power; cleaning, adjusting, testing and performing other preventive maintenance on a ship's boilers, main engines, turbogenerators and other auxiliary machinery including steering engines, elevators, winches, pumps and associated valves; operating and maintaining desalinization plants (distilling plants) to make fresh water from sea water; maintaining refrigeration plants, air conditioning systems and galley equipment; repairing or replacing valves, pumps, heat exchangers, compressors, steam turbines and hydraulic or pneumatic control devices; making entries in and analyzing machinery operating records and reports.

Detailed List of Required Duties

ASVAB Score Requirements: VE+AR+MK+AS=195 or VE+AR+MK+AO=200

Other Requirements: Must have normal hearing. 72 month obligation.

Notes: Normal hearing required. Frequencies: 3000hz 4000hz 5000hz 6000hz Average hearing threshold level in these four frequencies must be less than 30db, with no level greater than 45db in any one frequency. If hearing level exceeds these limits, the applicant is enlistment ineligible for the rating.

Technical Training Information: Enlistees are taught the fundamentals of this rating through on-the-job training or formal Navy schooling. Advanced technical and operational training is available in this rating during later stages of career development.

Engineering Common Core Mechanical Core Great Lakes, Ill. 3 weeks to 4 weeks

Introduction to technical documentation, basic mechanical theory, safety precautions and programs, alignment and operation of piping systems and equipment, hand tools, precision instruments, lubricants, bearings, couplings, gears, valves, pumps and the Maintenance Material Management System (3M) Group instruction and practical application

"A" Technical School Great Lakes, Ill. 4 weeks

Introduction to technical documentation, basic watch standing procedures, alignment and operation of piping systems and equipment, hand tools, precision instruments, lubricants and lubricating systems, bearings, couplings, gears, valves, the Maintenance Material Management System (3M), basic technical knowledge, terminology and watch standing procedures for the operation of conventional marine steam propulsion systems and preventive maintenance of plant equipment

After "A" School, MMs may be assigned to ships and naval repair activities afloat and at shore stations in the United States or overseas. During a 20-year period in the Navy, MMs spend about 70 percent of their time assigned to fleet units and 30 percent to shore stations. Shore assignments are normally at shore intermediate activities (SIMAs) as instructors in Class "A" or "C" Schools, as recruit company commanders or in recruiting duty.

Working Environment: Machinist's mates work within the hull of a ship in fire rooms, boiler rooms, engine rooms or shops. These locations are sometimes hot and noisy. MMs may be required to perform some heavy physical work. They must be able to work closely with others and, in some cases, with limited supervision

Opportunity Rating:

E-1 to E-4 E-5 E-6
3 3 3

1 = Currently undermanned
2 = Currently manned at desired levels
3 = Currently overmanned

Note: Levels are as of 10 December 2003. Subject to change without notice.

Advancement (Promotion) Trends

College Credits for Training/Experience

Career Progression

Above Information Courtesy of United States Navy

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