QMED (any rating) Exam Prep

USCG MMC — Qualified Member of the Engine Department (QMED)

The USCG Qualified Member of the Engine Department (QMED) is the ratings-level engine-department credential on a U.S.-flagged vessel. A QMED performs skilled engineering tasks below the officer level — operating auxiliaries, maintaining machinery, handling fuel and lube oil transfers, standing watch under an officer. The single QMED-Any Rating endorsement unlocks seven specific watch/work billets: Oiler, Fireman/Watertender, Electrician, Refrigerating Engineer, Junior Engineer, Machinist, and Pumpman/Pump Technician. The credential is issued under 46 CFR Part 12 Subpart C and aligns with STCW Code Table A-III/4 (Rating Forming Part of an Engineering Watch) and A-III/5 (Rating as Able Seafarer Engine).

Exam structure

The QMED exam is a multi-rating battery. For QMED-Any Rating, candidates sit all seven sub-rating exams in one sequence at a USCG REC (or NMC-approved proctor). Each sub-rating is its own module:

• Oiler (Q500) — 50 questions, 2 hours. Diesel lube and cooling systems, bearings, purifiers, watchkeeping.
• Fireman/Watertender (Q510) — 50 questions, 2 hours. Boiler operation, feedwater, combustion control, boiler casualty response.
• Electrician (Q520) — 50 questions, 2.5 hours. AC/DC machines, switchboards, batteries, motor starters, grounding.
• Refrigerating Engineer (Q530) — 50 questions, 2 hours. Vapor-compression cycle, refrigerants (including R-134a, R-404A, CO2), leak detection, ozone-depleting substance regulations under 40 CFR Part 82 and MARPOL Annex VI.
• Junior Engineer (Q540) — 70 questions, 3.5 hours. Combined diesel/steam auxiliary operation, standing a watch.
• Machinist (Q550) — 50 questions, 2 hours. Lathe and milling operations, precision measurement, bearing replacement, shaft alignment.
• Pumpman (Q560) — 50 questions, 2 hours (tankships). Cargo pumping systems, crude oil washing, inert gas systems, MARPOL Annex I operations.

Plus the Engineering Safety (Q440 / eng-safe) overlay — 50 questions, 2.5 hours — on fire, pollution, confined space, and general engine-room safety.

All modules pass at 70%. Rules of the Road is not part of the QMED exam; engine-department ratings don't stand navigational watches.

Eligibility & prerequisites

• Sea service on CG-719S: six months of service in the engine department of U.S.-flagged vessels (or equivalent training at a Coast Guard-approved program like SIU Paul Hall Center, MITAGS, or academy engineering cadet shipping). For QMED-Any Rating, additional service on ratings below QMED (Wiper, Coal Passer) accrues toward the six-month minimum.
• Medical certificate CG-719K with color-vision pass (critical for Electrician sub-rating).
• TWIC from TSA.
• STCW Basic Training (BT) — for international-route vessels.
• STCW A-III/4 or A-III/5 rating-level endorsement — requires documented task completion in an approved engineering rating Training Record Book per NVIC 18-14.
• Drug test (DOT 5-panel) within 185 days.
• Age 18 minimum.
• Practical demonstrations — signed assessments for pump operation, purifier operation, basic machining, and electrical safety lockout/tagout.

Study timeline

Most QMED candidates prep 10–16 weeks for QMED-Any Rating because of the seven-module breadth. Candidates who already hold a single sub-rating (say, Oiler) and are upgrading to Junior Engineer or adding Refrigerating Engineer plan 4–8 weeks per additional module.

What examiners look for

QMED questions are equipment-grounded and often numerical. Expect:

• Purifier gravity disc sizing for Oiler.
• Combustion air-fuel ratio and boiler water chemistry (alkalinity, phosphate, chloride limits) for Fireman/Watertender.
• Megohmeter readings, insulation resistance minimums, and grounded vs. ungrounded power distribution for Electrician.
• Refrigerant pressure-temperature correlations and compressor short-cycling causes for Refrigerating Engineer.
• Tank cleaning and inerting sequences per MARPOL Annex I and 46 CFR 32.53 for Pumpman.

The NMC sample QMED exam PDFs are the closest preview; questions repeat nearly verbatim across cycles.

Common pitfalls

• Underestimating Electrician — candidates from pure diesel backgrounds struggle with AC theory.
• Missing Refrigerating Engineer regulatory content — EPA Section 608 technician certification rules, ODS phase-out under Clean Air Act and MARPOL Annex VI.
• Pumpman questions on inert gas oxygen content (must be <8% by volume) and tank atmosphere testing are often poorly studied.
• Candidates frequently forget that Junior Engineer is a distinct module — it is not just "Oiler plus Fireman."
• No Rules of the Road 90% trap here, but the Engineering Safety (Q440) module has its own reg-heavy pitfall: MARPOL Annex I Oil Record Book Part I entries.

Study strategy using MMCE.app

Choose the Engineer → Rating track and select QMED-Any Rating as the target. MMCE.app's 620-question QMED bank is deliberately tight and high-yield — every item maps to an NMC published subject. Recommended workflow:

1. Module rotation — focus 3–4 days per sub-rating; the adaptive engine surfaces the weakest topic within each.
2. SM-2 flashcards for formulas (refrigeration PT charts, insulation resistance thresholds, boiler water limits).
3. AI tutor reviews each miss with the underlying system diagram and the relevant CFR citation — especially useful for Electrician and Refrigerating Engineer.
4. Weekly timed mini-exams per sub-rating (50 questions, 2 hours) to acclimate to the REC pace.
5. Final two weeks: full-battery dry run — all seven sub-ratings back to back, 12+ hours of testing, just like the real sitting.

Relevant publications

• Modern Marine Engineer's Manual (Hunt) — Vols. 1 & 2.
• Machinery's Handbook (Industrial Press) — the Machinist bible.
• Audel Refrigeration Home and Commercial and ASHRAE Handbook: Refrigeration — for Q530.
• Marine Electrical Practice (Watson) and NEC (NFPA 70) basics for Q520.
• 46 CFR Part 12 Subpart C and Part 15 (manning).
• 46 CFR Subchapter F (Marine Engineering) — Parts 56, 58, 61, 64.
• 46 CFR Subchapter J (Electrical Engineering) — Parts 110–113.
• 33 CFR 155 and MARPOL Annex I — Oil Record Book Part I.
• 40 CFR Part 82 — EPA Section 608 refrigerant handling.
• NVIC 18-14 — QMED endorsement guidance.

After you pass

The QMED MMC is valid five years. Renew with CG-719B, CG-719K, TWIC, and one year of sea service in the last five OR a USCG-approved refresher. STCW Basic Training and Advanced Firefighting (if held) revalidate every five years.

Upgrade path: QMED → Designated Duty Engineer (DDE) <1,000 HP → Third Assistant Engineer (with appropriate sea service and the Engineer Officer exam battery — Q420, Q430, Q460, Q440). Many QMEDs add Electro-Technical Rating (ETR) under STCW A-III/7, Tankerman-Assistant (PIC-A), or Refrigerated Container Technician. MMCE.app's upgrade path preserves your QMED question history and layers Engineer Officer modules — the same adaptive engine, a bigger credential, a substantial pay raise.