MMs operate, repair, and perform organizational
and intermediate level maintenance on ship propulsion
machinery, auxiliary equipment, and outside
machinery, such as steering engines, windlasses,
hoisting machinery, and elevators. MMs also operate
and perform maintenance on food preparation
equipment, laundry equipment, and refrigeration and
air-conditioning equipment. They also transfer and
inventory lubricating oils, maintain records and reports,
and may perform duties in the generation and storage
of industrial gases.
O C C U P A T I O N A L F I E L D 4 ( S H I P
MAINTENANCE). TMS occupational field includes
the Damage Controlman (DC), Hull Maintenance
Technician (HT), Instrumentman (IM), Machinery
Repairman (MR), Molder (ML), Opticalman (OM), and
Patternmaker (PM) ratings.
Damage Controlman. The insignia for the
Damage Controlman (DC) rating is the crossed fire ax
DCs perform organizational and intermediate level
maintenance and repair of damage control equipment
and systems. They plan, supervise, and perform tasks
necessary for damage control; ship stability;
preservation of watertight integrity; fire-fighting; and
chemical, biological, and radiological (CBR) warfare
defense. DCs also instruct and coordinate damage
control parties and instruct personnel in the techniques
of damage control and CBR defense. They additionally
supervise and perform tasks in procurement and
issuance of supplies and repair parts and prepare records
Hull Maintenance Technician.The insignia for
the Hull Maintenance Technician (HT) rating is the
crossed fire ax and maul with a carpenters square.
HTs plan, supervise, and perform tasks necessary
for fabrication, installation, and repair of all types of
shipboard structures and plumbing and piping systems.
HTs qualify in the techniques, skills, and use of damage
control and fire-fighting. They organize, supervise, and
train personnel in maintenance, hull repair, and damage
control duties. HTs also supervise and perform tasks in
procurement and issuance of supplies and repair parts.
Instrumentman. T h e i n s i g n i a f o r t he
Instrumentman (IM) rating consists of calipers.
IMs perform organizational and intermediate
maintenance on mechanical instruments, office
machines, and Navy timepieces. They implement Navy
or Mechanical Instrument Repair and Calibration Shop
Machinery Repairman. The insignia for the
Machinery Repairman (MR) rating consists of a
micrometer and gear.
MR perform organizational and intermediate
maintenance on assigned equipment and in support of
other ships, requiring the skillful use of lathes, milling
machines, boring mills, grinders, power hacksaws, drill
presses, and other machine tools. MRs are also required
to be skillful in the use of portable machinery, hand
tools, and measuring instruments found in machine
Molder. The insignia for the Molder (ML) rating
consists of a crossed bench rammer and stove tool.