This guide provides helpful information for those considering to enlist in the Navy Reserve as a Machinist’s Mate – Submarine, Auxiliary (MMA) during Fiscal Year 2025.
Submarines rely on more than stealth—they depend on machinery that never fails.
As a Navy Reserve Machinist’s Mate – Submarine, Auxiliary (MMA), you will keep these systems alive beneath the ocean’s surface.
From hydraulics to air systems, your skills will keep the mission running.
Ready to dive deeper? Keep reading.
Job Role and Responsibilities
Machinist’s Mate – Submarine, Auxiliary (MMA) in the Navy Reserve maintains and repairs mechanical systems aboard submarines. They operate air, hydraulic, and emergency systems that keep the submarine mission-ready.
MMA personnel in the Navy Reserve perform technical support for active-duty submarines. They operate and repair auxiliary equipment undersea.
Daily Tasks
Submarine ITRs handle a wide array of essential technical duties each day. These responsibilities require not only mechanical skill but also precise attention to operational integrity and safety protocols.
Key daily tasks include:
- Operating onboard systems such as hydraulics, refrigeration units, air circulation, and ventilation mechanisms
- Performing routine maintenance on auxiliary machinery and critical damage control equipment
- Troubleshooting technical issues, identifying faults in mechanical systems, and executing necessary repairs
- Overseeing system operations, supervising equipment functionality, and maintaining accurate technical records
This role blends hands-on engineering with real-time problem-solving, demanding both physical coordination and mental agility.
Specific Roles
MMAs serve in technical positions aboard submarines, each assigned specific Navy Enlisted Classifications (NECs).
These roles define their responsibilities and areas of expertise.
| NEC Code | Title | Description |
|---|---|---|
| 4230 | Submarine Auxiliary Systems Technician | Maintains and repairs submarine auxiliary systems, including hydraulic plants and atmosphere control equipment. |
| 4299 | Machinist’s Mate Basic | Operates and maintains submarine mechanical systems, including air conditioning, refrigeration, and hydraulic systems. |
| 42A9 | Machinist’s Mate, Non-Nuclear, Auxiliary (Submarines) | Operates and maintains auxiliary machinery critical to submarine operations. |
| 9502 | Instructor | Trains personnel in technical skills and maintenance procedures related to submarine auxiliary systems. |
| 4805 | Diesel Engine Inspector | Conducts inspections and certifies operational readiness of diesel engines aboard submarines and support vessels. |
| 4206 | Atmosphere Control Equipment Technician | Maintains and repairs atmosphere control and air purification systems on submarines. |
Each NEC corresponds to specialized duties essential to submarine survivability and mission success.
Mission Contribution
MMA personnel sustain the submarine’s mechanical readiness. They keep life-support and emergency systems operational undersea. Their work secures the vessel’s endurance and survivability.
Technology and Equipment
MMAs operate air compressors, diesel engines, refrigeration units, and hydraulic tools. They work with submarine-specific damage control systems and classified machinery.
Work Environment
The daily environment for Machinist’s Mates (Auxiliary) combines high-stakes machinery management with a rigid operational structure. This role is embedded deep within submarine culture—physically tight, procedurally strict, and intensely mission-focused.
Setting and Schedule
MMAs operate inside mechanical compartments and shipboard spaces where movement is limited and spatial awareness is critical. Most of the work happens indoors, though extended deployments at sea shift the context entirely.
- Primary location: Submarines and submarine shore-based support facilities
- Physical conditions: Confined spaces, tight quarters, high noise levels
- Work rhythm: Rotational shifts, including overnights and weekends
- Deployment model: Long-duration patrols with minimal shore breaks
This cycle of routine and disruption shapes every aspect of the MMA schedule.
Leadership and Communication
Operational clarity is non-negotiable. MMAs follow a command-driven structure where every instruction is delivered with precision.
- Orders move top-down—from Chief of the Boat to Engineering supervisors to enlisted MMAs
- Communication is technical, protocol-driven, and always time-sensitive
- Evaluations and feedback are formal, structured around scheduled reviews and post-operation briefings
This system eliminates ambiguity and reinforces operational reliability.
Team Dynamics and Autonomy
Functioning in compact teams, MMAs are both highly collaborative and independently accountable. Shared responsibilities don’t dilute individual ownership.
- Small, task-specific teams dominate the workflow
- Independent repair work and diagnostics are routine
- Critical systems often rely on one-person decisions during underway failures
Decision-making at the individual level is not only expected but required in time-sensitive scenarios.
Job Satisfaction and Retention
The role offers a strong sense of technical ownership. Success isn’t abstract—it’s measured in uptime, readiness, and flawless operation.
- Retention rates trend moderate
- Satisfaction stems from technical mastery and vital mission contributions
- Deployment fatigue and social isolation are the main drivers of attrition
For those who thrive on mechanical precision and value critical infrastructure roles, the environment proves rewarding. For others, the constraints can erode long-term satisfaction.
Training and Skill Development
Initial Training
MMAs complete Navy Recruit Training followed by specialized technical instruction.
| Training Phase | Location | Duration | Focus Areas |
|---|---|---|---|
| Navy Recruit Training | Great Lakes, Illinois | 9 weeks | Naval customs, discipline, basic seamanship |
| Basic Enlisted Submarine School (BESS) | Groton, Connecticut | 9 weeks | Submarine safety, ship systems, emergency procedures |
| Machinist’s Mate “A” School | Great Lakes, Illinois | 9 weeks | Auxiliary systems, mechanical theory, maintenance |
| Submarine Systems Training | Groton, Connecticut | Varies by NEC | Advanced submarine auxiliary operations |
Advanced Training
Opportunities exist for NEC-specific and leadership courses. MMAs may qualify for advanced technical schools in damage control, atmosphere control, or diesel systems.
The Navy supports development through rate-specific C-Schools and leadership academies.
Physical Demands and Medical Evaluations
Physical Requirements
MMAs meet Navy Reserve physical fitness standards and perform physically demanding tasks daily.
Work requires frequent lifting, climbing, crawling, and working in confined spaces aboard submarines.
| Activity | Frequency | Notes |
|---|---|---|
| Lifting heavy equipment | Regular | Up to 70 lbs. during maintenance operations |
| Climbing ladders | Frequent | Vertical and inclined ladders onboard |
| Working in tight spaces | Constant | Inside engine rooms and mechanical spaces |
| Standing for long periods | Regular | During operations and inspections |
Physical Readiness Test (PRT) – Navy Reserve 2025
| Event | Male (17-19) Minimum | Female (17-19) Minimum |
|---|---|---|
| Push-ups | 42 | 17 |
| Plank | 1:22 min | 1:22 min |
| 1.5-mile run | 13:30 min | 15:30 min |
Medical Evaluations
MMAs must pass a Navy physical exam and submarine duty medical screening.
Periodic medical evaluations include audiograms, cardiovascular assessments, and fitness-for-duty exams.
Submarine-specific clearances require pressure and respiratory capability testing.
Deployment and Duty Stations
Deployment Details
Navy Reserve MMAs deploy for periods between 3 and 12 months. They crew submarines during patrols and extended undersea operations.
They also deploy to submarine tenders and forward maintenance units. Their mission is to maintain readiness, repair systems, and sustain combat capability at sea.
Deployments cover both Atlantic and Pacific theaters. MMAs operate aboard submarines in contested waters and strategic patrol zones.
Shore assignments send them to submarine bases, repair yards, and forward-deployed facilities.
Location Flexibility
Submarine Reserve MMAs receive orders based on fleet demands. Groton, Kings Bay, Bangor, Pearl Harbor, Guam, and Diego Garcia are common assignments.
Reservists request duty stations through official channels, but the fleet dictates placement. MMAs serve where submarines are stationed and where repairs are needed.
Career Progression and Advancement
Career Path
Navy Reserve MMAs follow a defined path from apprentice to senior technical leader.
| Paygrade | Typical Time-in-Rate | Responsibilities |
|---|---|---|
| E-1 to E-3 (Apprentice) | 12-36 months | Basic system operations, preventive maintenance |
| E-4 (Petty Officer Third Class) | 12-24 months | Advanced repairs, team support, technical troubleshooting |
| E-5 (Petty Officer Second Class) | 36 months | Lead maintenance crews, supervise junior sailors |
| E-6 (Petty Officer First Class) | Varies | Manage system readiness, training, and inspections |
| E-7+ (Chief Petty Officer and above) | Varies | Senior leadership, departmental oversight |
Promotion and Growth Opportunities
MMAs advance based on performance evaluations, time-in-rate, and exam scores. Leadership courses and advanced NEC qualifications improve promotion chances.
Chief Petty Officer (E-7) marks a key leadership milestone, unlocking supervisory and departmental command roles.
Specialization Opportunities
MMAs can pursue specialized NECs, such as:
- 4230: Submarine Auxiliary Systems Technician
- 9502: Instructor
- 4805: Diesel Engine Inspector
- 4206: Atmosphere Control Equipment Technician
The complete list was provided in an earlier section.
Role Flexibility and Transfers
MMAs may transfer into related mechanical or engineering roles within the Navy Reserve.
Lateral moves to damage controlman or engineering technician positions are common. Requests follow Navy Reserve guidelines and require command approval.
Performance Evaluation
MMAs are evaluated through Enlisted Advancement Worksheets (EAW) and periodic command reviews.
Leadership, technical skills, and system readiness drive advancement decisions. Consistent, high-performance ratings enable promotion and specialized duty assignments.
Compensation, Benefits, and Lifestyle
Financial Benefits
Navy Reserve MMAs receive standard military pay and allowances. Compensation includes base pay, Reserve drill pay, and special duty pay if assigned to submarine platforms.
| Pay Component | Description | 2025 Example (E-4 with <2 Years) |
|---|---|---|
| Base Pay | Standard Reserve monthly base pay | $2,503.20 |
| Drill Pay | Pay per drill weekend (4 drills/month) | $417.20 |
| Submarine Duty Incentive Pay (SDIP) | Monthly bonus for submarine-qualified personnel | $75 – $425 |
| Clothing Allowance | Annual uniform maintenance allowance | $327.60 |
| Enlistment/Reenlistment Bonuses | Bonuses for critical skills or high-demand NECs | Varies by rating and NEC |
Additional Benefits
Technical know-how isn’t the only return on investment. This position brings a layered package of long-haul incentives—financial, educational, and structural—tailored for Reservists operating inside and outside the uniform.
- TRICARE Reserve Select
Full medical coverage isn’t an upgrade—it’s standard. Low monthly cost, wide provider access, and full inclusion of dependents make it a practical backbone for health security. - VA-Guaranteed Home Financing
No down payment. No private mortgage insurance. Government-backed loans designed to lower financial barriers to homeownership—engineered for those who serve. - MGIB-SR Education Support
Whether it’s night classes, welding certification, or a four-year degree, this benefit transfers directly into tuition support. Covers a wide range of programs, flexible for Reservist schedules. - Sub Base Housing Access
Space-available housing at submarine installations comes at significantly reduced rates. Not guaranteed, but when it’s open, the cost-to-location value is difficult to match. - Deferred Reserve Retirement
Twenty qualifying years initiates eligibility for military pension. Payments begin later in life, but accumulate as dependable post-career income—a rare benefit in today’s job market.
These aren’t fringe perks—they’re structural. Each exists to extend the practical value of service far beyond deployment cycles and into long-term personal infrastructure.
Work-Life Balance
Reservists complete drill weekends monthly and annual training periods of two weeks.
Additional mobilizations occur based on operational needs.
Outside of mobilizations, Reservists maintain civilian employment or education, enabling more control over personal and family life compared to active-duty counterparts.
Risk, Safety, and Legal Considerations
This role isn’t just technical—it’s inherently high-risk. The work environment combines mechanical volatility, legal constraints, and personal sacrifice. Every task occurs under regulated scrutiny with no margin for error.
Job Hazards
Daily exposure to hazardous machinery and operational threats defines this position. MMAs don’t just work around danger—they work inside it.
- High-speed rotating shafts, pressurized lines, and chemical systems are routine
- One misstep with hydraulic systems or ventilation units can trigger cascading failure
- Fire, flooding, or toxic gas emergencies carry elevated consequences in a submarine environment
- At-sea isolation compounds the risk—external support is delayed or unavailable
Every system maintained is capable of injury—or worse—if mishandled or neglected.
Safety Protocols
Safety is non-negotiable. Procedures aren’t guidelines—they’re mandatory operations enforced at every level.
- Lockout/tagout protocols are enforced before all maintenance activities
- Weekly damage control drills simulate fire, flooding, and gas events
- Personal protective equipment (PPE) is required for all technical work
- NAVOSH compliance is built into every process—from tools to task logs
- Supervisor oversight ensures strict adherence and initiates immediate corrections
The system is designed to catch mistakes before they become fatalities.
Security and Legal Requirements
Operating in this space requires legal vetting and full federal trust.
- Secret clearance is mandatory; investigations cover finances, background, and personal conduct
- Medical and psychological screenings assess submarine duty fitness
- Reservists follow lawful orders, with zero exemption under mobilization
- Deployment orders may include hazardous or contested areas, with legal implications tied to compliance
Non-compliance isn’t just a policy issue—it’s a criminal matter under U.S. Code.
Impact on Family and Personal Life
Family Considerations
Submarine Reserve duty disrupts family structure by design. The schedule isn’t flexible, and communication is often nonexistent for extended periods.
- Long-term absences and irregular mobilizations challenge household stability
- Months without contact during patrols are routine
- Family members often depend on support services—readiness groups, counseling, and Navy resources—to bridge the gap
- Reservists must navigate dual commitments: mission obligations and civilian responsibilities
This lifestyle is demanding—not just on the sailor, but on everyone connected to them.
Relocation and Flexibility
Stability exists—but only within the limits of Navy operational needs.
- Most Reservists remain based near home units, but mobilizations may redirect them to sub bases or overseas stations
- Relocation can be short-notice, and assignments may extend unpredictably
- While some geographic consistency is possible, flexibility is built into the contract
Home roots are respected—but not guaranteed.
Post-Service Opportunities
Transition to Civilian Life
MMA technical training transitions smoothly into civilian industries that value precision, discipline, and system-level engineering.
- Roles include marine engineering, diesel mechanics, HVAC maintenance, and industrial systems
- Many veterans move into power plant operations, shipyard work, or defense contracting
- Skills are directly transferable with minimal retraining
The private sector often views this service background as plug-and-play for high-responsibility roles.
Transition Assistance Programs
The Navy structures multiple tools to ensure veterans don’t exit the service without a landing path.
- Transition briefings and workshops prepare service members for civilian job markets
- VA-backed counseling and education benefits support career shifts
- Navy COOL (Credentialing Opportunities On-Line) connects MMA experience to recognized civilian certifications and licenses
- Resume writing, job placement, and interview prep are provided at no cost
These programs transform military service into post-service momentum—practically, not theoretically.
Civilian Career Prospects
| Civilian Career | Industry | Median Salary (BLS) |
|---|---|---|
| Industrial Machinery Mechanic | Manufacturing | $60,330 |
| Marine Engineering Technician | Shipbuilding | $66,030 |
| Diesel Technician | Transportation | $58,970 |
| HVAC Technician | Construction | $51,390 |
| Power Plant Operator | Utilities | $94,790 |
Qualifications, Requirements, and Application Process
Basic Qualifications
| Requirement | Details |
|---|---|
| Age | 17-39 years old (Reserve) |
| Citizenship | U.S. citizen or legal permanent resident |
| Education | High school diploma or GED (Tier I or II) |
| Vision | Correctable to 20/20 |
| Hearing | Normal hearing required |
| Medical Screening | Submarine duty physical, pressure test, and medical clearance |
| Security Clearance | Eligible for Secret clearance |
ASVAB Requirements
| Requirement | Minimum Standard |
|---|---|
| AFQT Score | 31 minimum (Tier I education) Navy Reserve |
| Line Scores | VE+AR+MK+MC = 210 or VE+AR+MK+AO = 210 for MMA rating |
| Testing Methods | ASVAB, PiCAT (internet), or AFCT (paper) authorized for qualification |
Application Process
- Meet with a Navy Reserve recruiter. Discuss eligibility and MMA rating options.
- Take ASVAB, PiCAT, or AFCT. Verify line scores for MMA qualification.
- Complete MEPS processing. Medical exam, background check, and security interview.
- Receive clearance screening. Must qualify for Secret clearance.
- Choose MMA rating and NEC path. Based on line scores and service needs.
- Sign enlistment contract. Finalize Reserve agreement.
- Ship to Recruit Training Command. Complete boot camp, BESS, and “A” School.
Selection Criteria and Competitiveness
MMA applicants compete across several categories:
- ASVAB Line Scores: Higher scores improve selection chances.
- Mechanical Aptitude: Prior trade, vocational, or mechanical work strengthens application.
- Submarine Eligibility: Pass submarine duty physical and psychological screening.
- Fitness Standards: Must meet Navy PRT minimums.
- Leadership Potential: Documented leadership roles enhance competitiveness.
Additionally, Reservists with civilian technical certifications, such as welding, HVAC, or diesel mechanics, increase promotion and billet assignment potential.
Is This a Good Job for You? The Right (and Wrong) Fit
Ideal Candidate Profile
This role is built for the mechanically minded—individuals who thrive in hands-on environments, solve problems under pressure, and operate efficiently when space is limited and expectations are high.
Technical and Personal Traits
Machinist’s Mates (Auxiliary) must bring both physical ability and mental sharpness. Success is defined by performance under pressure and precision in execution.
- Comfort with tools and mechanical systems is a must
- Attention to detail under stress is critical
- Endurance, patience, and discipline are non-negotiable on long submarine patrols
- Physical strength and mental toughness must match the demands of confined, high-noise environments
- Isolation tolerance—essential for surviving the operational tempo of undersea missions
Preferred Backgrounds
Candidates with the following experience often transition smoothly into the role:
- Automotive repair and diagnostics
- HVAC installation or maintenance
- Diesel engine service and overhauls
- Operation or repair of industrial machinery
- Heavy equipment handling in construction or manufacturing
Individuals who enjoy mechanical problem-solving, appreciate routine with a purpose, and perform well in small, high-functioning teams typically excel.
Potential Challenges
This job does not operate in a comfort zone. The environment is physically intense, psychologically straining, and relentlessly procedural.
- Confined spaces and constant exposure to heat, vibration, and mechanical noise
- Disrupted sleep schedules and long shifts extend beyond typical work hours
- Persistent fatigue, compounded by irregular watch cycles
- Zero access to family communication during patrols, often lasting months
- Cumulative psychological stress from isolation, mission pressure, and spatial restriction
Misalignment Indicators
This role is not a fit for individuals who:
- Require open or flexible workspaces
- Dislike manual labor, machinery, or routine troubleshooting
- Avoid high-stress environments or potential hazards
- Need regular family interaction or personal space
This isn’t a job to ease into—it’s a role that demands full buy-in from day one.
Career and Lifestyle Alignment
MMAs fit technical-minded individuals seeking demanding roles. The rating supports future work in shipyards, power plants, or industrial facilities.
Moreover, submarine experience translates into careers in commercial diving, maritime maintenance, and defense contracting.
Those who value skill mastery, team loyalty, and operational discipline will excel.
MMAs develop leadership and crisis management skills. The rating suits those aiming for technical leadership or specialized mechanical fields after service.
More Information
If you wish to learn more about becoming an Machinist’s Mate – Submarine, Auxiliary (MMA) in the Navy Reserve, contact your local Navy Enlisted Recruiter. They will provide you with more detailed information you’re unlikely to find online.
You may also be interested in the following related Navy Reserve Enlisted jobs:
- Information Systems Technician – Submarine, Radio (ITR)
- Torpedoman’s Mate (TM)
