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Coast Guard Rating · Engineering

MK Machinery Technician

Current service use not established

This code is listed in the directory. Inclusion alone does not confirm current service use.

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Overview

A Machinery Technician operates, maintains, and repairs engines, boilers, steam turbines, propulsion equipment, and auxiliary machinery. The technician also services refrigeration, air conditioning, electrical, and machine shop equipment, leads damage control repair parties, and performs maintenance administration.

Core Skills

  • Hydraulic machinery maintenance and repair
  • Shipboard propulsion system maintenance

Civilian Career Paths

Career associations are editorial assessments of the cited evidence, not an official crosswalk unless the evidence explicitly says so. O*NET supplies civilian occupation information, not proof of a military match. Related experience does not confer civilian qualifications. Tasks and tools below describe civilian work, not military training.

Motorboat Mechanics and Service Technicians

MK experience maintaining vessel engines, hydraulics, and propulsion systems transfers directly to motorboat mechanical maintenance and repair.

How to prepare: Complete hands-on training in the engine diagnostic scanners used by a prospective marine service employer.

What the civilian work involves
  • Start motors and monitor performance for signs of malfunctioning, such as smoke, excessive vibration, or misfiring.
  • Repair engine mechanical equipment, such as power tilts, bilge pumps, or power take-offs.
  • Perform routine engine maintenance on motorboats, such as changing oil and filters.
Civilian tools and software (examples)
  • CDI Electronics M.E.D.S.
  • Engine diagnostic scanners

Ship Engineers

MK maintenance of shipboard propulsion and mechanical systems provides directly relevant machinery knowledge for ship engineering work.

How to prepare: Request an official sea-service transcript or assignment history with vessel tonnage, routes, propulsion power, time underway, and assigned duties for Coast Guard evaluation toward an appropriate engineering endorsement. A DD-214 is not acceptable sea-service evidence, and the Coast Guard determines the equivalent merchant service and endorsement level.

What the civilian work involves
  • Monitor engine, machinery, or equipment indicators when vessels are underway, and report abnormalities to appropriate shipboard staff.
  • Monitor and test operations of engines or other equipment so that malfunctions and their causes can be identified.
  • Start engines to propel ships, and regulate engines and power transmissions to control speeds of ships, according to directions from captains or bridge computers.

Bus and Truck Mechanics and Diesel Engine Specialists

MK engine and hydraulic machinery repair experience transfers to vehicle maintenance, with additional preparation for road-vehicle systems.

How to prepare: Take a practical heavy-vehicle course covering brake, steering, and wheel-bearing inspection to address systems outside the verified MK duties.

What the civilian work involves
  • Inspect brake systems, steering mechanisms, wheel bearings, and other important parts to ensure that they are in proper operating condition.
  • Raise trucks, buses, and heavy parts or equipment using hydraulic jacks or hoists.
  • Attach test instruments to equipment, and read dials and gauges to diagnose malfunctions.
Civilian tools and software (examples)
  • Cummins INSITE
  • Computerized maintenance management system software CMMS

Training & Development

Choose credentials for your target role. COOL funding markers describe program listings, not a guarantee of eligibility or funding.

Getting Started

  • USCG Merchant Mariner Credential

    Obtain the engineering endorsement appropriate to the intended shipboard position; the MMC authorizes service only within its endorsed capacities or permitted lower capacities.

    Eligibility and preparation: Meet the requirements of each endorsement sought, including required sea service; hold or have applied for a TWIC; satisfy applicable vision, hearing, medical, and physical standards; and provide evidence of a qualifying drug test or exemption.

    For: Ship Engineers

Notes & Sources

Evidence for this guidance (6 documents)
  1. USCG authority snapshot: MK Machinery Technician

    [1] data/authority/coast_guard-codes.json entry MK (COOL USCG MOC Feed (uscg.json) + Go Coast Guard - Enlisted Careers (gocoastguard.com)); fetched 2026-07-25

    Supports: Hydraulic machinery maintenance and repair, Shipboard propulsion system maintenance, Motorboat Mechanics and Service Technicians (O*NET 49-3051.00), Ship Engineers (O*NET 53-5031.00), Bus and Truck Mechanics and Diesel Engine Specialists (O*NET 49-3031.00)

  2. O*NET: Motorboat Mechanics and Service Technicians

    [2] O*NET 30.3 occupational data

    Supports: Motorboat Mechanics and Service Technicians (O*NET 49-3051.00)

  3. O*NET: Ship Engineers

    [3] O*NET 30.3 occupational data

    Supports: Ship Engineers (O*NET 53-5031.00)

  4. USCG: 46 CFR 10.232 military sea-service evidence and credit

    [4] Paragraphs (a) and (d)(1), official eCFR snapshot September 21, 2026; retrieved September 24

    Supports: Ship Engineers (O*NET 53-5031.00)

  5. eCFR: 46 CFR part 10 - Merchant Mariner Credential issuance requirements

    [5] 46 CFR 10.201, 10.209 and 10.225; official eCFR XML API as of 22 September 2026

    Supports: Ship Engineers (O*NET 53-5031.00), USCG Merchant Mariner Credential

  6. O*NET: Bus and Truck Mechanics and Diesel Engine Specialists

    [6] O*NET 30.3 occupational data

    Supports: Bus and Truck Mechanics and Diesel Engine Specialists (O*NET 49-3031.00)

Defense contractor jobs for MK

Descriptions may be summarized for clarity. Verify all information with your branch career counselor or official military documentation before making career decisions.

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