MMA – Machinist’s Mate, Non-Nuclear, Submarine Auxiliary

Machinist’s Mates, Non-Nuclear, Submarine Auxiliary (MMA):

Some people call the reactor the heart of a submarine. Without A‑Gang, the crew still cannot operate for long.

As a Machinist’s Mate Auxiliary (MMA), you keep the submarine running in the most basic ways. You help make the air breathable, you help keep water available for drinking and daily use, and you also support systems that make the boat livable.

Your work touches major equipment across the submarine, including oxygen systems, water systems, heating, hydraulics, high‑pressure air, and diesel engines. If a system moves, pumps, or helps power the boat, you may be the one working on it. While others focus on the mission, you help keep the boat operating.

ENLISTMENT BONUS:
Future Navy MMAs are currently eligible to receive up to $10K in cash bonus just for signing up.

Machinist’s Mates, Non‑Nuclear, Submarine Auxiliary (MMA) are enlisted Sailors who operate, maintain, and repair many systems on submarines. Their work covers damage control gear, internal combustion diesel engines, hydraulic systems, atmosphere control equipment, refrigeration systems, compressed air and gas systems, water systems, plus sanitary and plumbing systems.

MMAs help keep submarines livable and ready to operate. If oxygen systems fail, the crew cannot stay underway. If drinking water is not available, operations cannot continue. A‑Gang keeps critical systems working so the submarine can do its job.

• Mostly on submarines, U.S. and international waters.
• Occasional shore duty, but the job is mostly at sea.
• Work in auxiliary spaces, often with minimal supervision.

• Generate and store oxygen. No air, no crew.
• Remove carbon dioxide, carbon monoxide, and hydrocarbons from breathable air.
• Maintain and repair emergency diesel engines, watertight doors, hatches, masts, and antenna hoists.
• Fix, replace, and inspect onboard equipment – valves, pumps, filters, compressors, hydraulic and pneumatic systems.
• Operate and repair refrigeration units and water desalination plants.
• Maintain air conditioning and galley equipment.
• Log and analyze machinery records and reports.

MMA is a hands‑on, physically demanding role. You work in tight spaces, with heavy machinery, under pressure. If it breaks, you fix it. If it fails, the whole sub feels it.

Keeps everything running, makes sure the right people are doing the right work.

• In charge of hydraulic power plants, diesel engines, atmosphere control, sanitation systems.
• Trains and supervises the crew keeping things operational.

The one turning the wrenches, running the systems, making sure nothing breaks.

• Operates diesel engines, firefighting systems, emergency dewatering, air conditioning, and more.
• Keeps water, air, and power systems functioning.
• Knows electrical safety, steam propulsion, hydraulic power plants.
• Fixes leaks, replaces valves, fabricates parts, whatever needs doing.

If something’s broken, they figure it out and fix it.

• Oversees system operations, making sure everything is working as it should.
• Keeps maintenance records, tracks repairs, logs test results.
• Diagnoses and repairs failures before they turn into bigger problems.

Everyone in A‑Gang has a job. If systems fail, there’s no backup crew—just them.

• Housing allowance (BAH): A tax‑free allowance when you live off base. Rates depend on pay grade, location, and dependency status.
• Food allowance (BAS):
  Enlisted Sailors receive $476.95 per month in 2026. See the BAS rates.
• Career Sea Pay:
  Extra monthly pay for qualifying sea duty. Amounts depend on pay grade and sea time. See the Career Sea Pay table.
• Submarine Duty Incentive Pay:
  Monthly submarine pay for qualified Sailors assigned to submarine duty. Amounts depend on pay grade and years of service. See the submarine pay table.
• Bonuses and incentives:
  The Navy may offer enlistment, skill, or reenlistment bonuses for certain training pipelines and manning needs.
• Healthcare:
  Medical and dental care through…