Machinist's Mate (MM)
Machinist's Mates are responsible for the continuous operation of the many engines, compressors, gears, refrigeration and air-conditioning equipment along with other types of machinery onboard ships and shore installations. They are responsible for the ship's steam propulsion and auxiliary equipment and the outside (deck) machinery. Machinist's Mates are deployed on-board nuclear powered ships to maintain the machinery and piping in nuclear reactors.
Machinist's Mates (MMs) 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.
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.
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.
A-School (Job School) Information
Great Lakes, IL -- 8 weeks
Security Clearance Requirement: None
Other Requirements
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.
Sea/Shore Rotation for This Rating- First Sea Tour: 54 months
- First Shore Tour: 36 months
- Second Sea Tour: 36 months
- Second Shore Tour: 36 months
- Third Sea Tour: 36 months
- Third Shore Tour: 36 months
- Fourth Sea Tour: 36 months
- Forth Shore Tour: 36 months
Note: Sea tours and shore tours for sailors that have completed four sea tours will be 36 months at sea followed by 36 months ashore until retirement.