- How the National Chief Mate Unlimited Exam Is Built
- The Ten Modules at a Glance
- Rules of the Road and Deck General (Q100-Q102)
- Deck Safety and Stability Problems (Q103-Q104)
- Navigation General: Near Coastal vs. Oceans (Q105-Q106)
- Chart Plot and Navigation Problems (Q107-Q109)
- Why Not Every Candidate Sits All Ten
- Sequencing the Modules in Your Preparation
- Frequently Asked Questions
- The USCG National Maritime Center publishes ten ONC01 chief mate modules, Q100 through Q109, and the topic lists are unweighted.
- Q105 and Q106 are route alternatives: Near Coastal candidates use Q105, Oceans candidates use Q106.
- Your USCG approval-to-test, not a ten-module checklist, determines exactly which modules you are assigned.
- Q104 stability problems and Q107 chart plot reward calculation drills far more than reading.
How the National Chief Mate Unlimited Exam Is Built
The National Chief Mate Unlimited (Oceans or Near Coastal) examination is administered under the United States Coast Guard National Maritime Center (NMC). Unlike many professional certifications, it is not a single sitting with a published percentage-weight blueprint. Instead, the NMC organizes the examination into discrete modules under the ONC01 chief mate exam series, each with its own topic scope. Those module topics are official, but they are unweighted: the NMC does not publish domain percentages, so any site claiming "Domain 4 is 18% of the exam" for this credential is inventing numbers.
This guide walks through all ten content areas, Q100 through Q109, explains what each one actually covers, and shows how they fit together. If you are new to the credential itself, start with What Is USCG-CM-UNL? and the eligibility and prerequisites breakdown, then return here to plan your module-by-module preparation. You can also test your readiness at any point with the practice test platform.
The Ten Modules at a Glance
The modules fall into three clusters: rules and general deck knowledge, safety and stability, and navigation. The table below maps each module code to its focus.
| Module | Name | Core Focus |
|---|---|---|
| Q100 | Rules of the Road - International and Inland | COLREGS, Inland Rules, safe watchkeeping |
| Q101 | Deck General Part I | Ship handling, pilot stations, maritime law, shipboard management |
| Q102 | Deck General Part II | Watchkeeping principles, 33 CFR 164, cargo handling and stowage |
| Q103 | Deck Safety | Stability concepts, damage, fire, abandon ship, lifesaving, search and rescue |
| Q104 | Deck Safety/Stability Problems | Trim, stability, damage stability and stress calculations |
| Q105 | Navigation General - Near Coastal | Piloting, compasses, publications, weather, tides |
| Q106 | Navigation General - Oceans | Q105-type material plus nautical astronomy and celestial navigation |
| Q107 | Chart Plot | Piloting, chart fixes, dead reckoning, electronic navigation |
| Q108 | Navigation Problems - Near Coastal | Ocean track/Mercator sailing, ETA, fuel, tide calculations |
| Q109 | Navigation Problems - Oceans | Great-circle, celestial fixes, twilight times, azimuth and amplitude |
Rules of the Road and Deck General (Q100-Q102)
Domain 1: Q100 Rules of the Road - International and Inland
Q100: COLREGS, Inland Rules and Safe Watchkeeping
This module tests both rule sets, and the real challenge is keeping them separate under pressure. Candidates must know which regime governs a given situation and answer accordingly.
- Steering and sailing rules: give-way and stand-on responsibilities in crossing, overtaking and head-on situations
- Lights, shapes and sound signals, including differences between International and Inland practice
- Restricted visibility conduct and safe speed
- Safe watchkeeping principles that tie the rules to bridge practice
Because Rules of the Road concepts surface again in watchkeeping and navigation-safety questions elsewhere, Q100 is a sensible foundation. Many candidates treat it as the "easy" module and are caught out by Inland-versus-International distinctions, so do not skim it.
Domain 2: Q101 Deck General Part I
Q101: Maneuvering, Law and Management
Q101 is the broadest "professional knowledge" module in the series. It blends seamanship with legal and managerial content that a chief mate handles daily.
- Maneuvering and handling, including pilot stations
- Operating in rivers, estuaries and shallow water, where squat and bank effects matter
- Maritime law and credentialing
- Shipboard management and personnel training
Domain 3: Q102 Deck General Part II
Q102: Watchkeeping, 33 CFR 164 and Cargo
Q102 moves from ship handling to systems of work: how the bridge is run and how cargo is loaded, stowed and carried safely.
- Basic principles of watchkeeping
- Navigation safety requirements under 33 CFR 164, including bridge equipment and procedures
- Cargo handling and stowage
Deck Safety and Stability Problems (Q103-Q104)
Domain 4: Q103 Deck Safety
Q103: Emergencies, Lifesaving and Search and Rescue
Q103 is the conceptual safety module. It covers what a chief mate must understand to keep a vessel and her people safe, and to respond when things go wrong.
- Construction, stability, trim and damage concepts
- Grounding, refloating, collision response and temporary repairs
- Passenger safety
- Fire and abandoning ship
- Emergency steering
- Lifesaving rules and operation
- Search and rescue, including AMVER and IAMSAR
Domain 5: Q104 Deck Safety/Stability Problems
Q104: Calculated Stability, Trim and Stress
Where Q103 asks what and why, Q104 asks "how much." This is a problem-solving module covering trim, stability, damage stability and stress calculations.
- Trim and draft calculations after loading, discharging or shifting weights
- Stability calculations and interpretation of the results
- Damage stability scenarios
- Stress calculations
The two modules are deliberately paired. A candidate who understands free-surface effect conceptually in Q103 should be able to carry the numbers in Q104. Study them back to back so the theory and the arithmetic reinforce each other. For a sense of how demanding calculation-heavy modules feel in practice, see How Hard Is the USCG-CM-UNL Exam?.
Navigation General: Near Coastal vs. Oceans (Q105-Q106)
Domain 6: Q105 Navigation General - Near Coastal
Q105: Piloting, Compasses, Weather and Tides
Q105 is the theory module for the Near Coastal route.
- Piloting: distances, bearings, fixes, charts and dead reckoning
- Instruments, aids to navigation, publications and notices
- Magnetic and gyro compass work, including error correction
- Azimuth and amplitude observations and terrestrial fixes
- Meteorology, weather, ocean currents, reports and tides
- Safe watchkeeping
Domain 7: Q106 Navigation General - Oceans
Q106: Q105 Territory Plus Celestial
Q106 covers the relevant piloting, charts, dead reckoning, aids, instruments, publications, compass, weather, tides and watchkeeping material, then adds the celestial layer.
- Nautical astronomy
- Celestial navigation, including Polaris observations
- Celestial fixes
- Star identification and star selection
- Meridian transit
| Topic | Q105 Near Coastal | Q106 Oceans |
|---|---|---|
| Piloting, charts, dead reckoning | Yes | Yes (relevant portions) |
| Compass error, weather, tides | Yes | Yes (relevant portions) |
| Nautical astronomy | No | Yes |
| Celestial fixes, Polaris, star selection, meridian transit | No | Yes |
Key Takeaway
Q105 and Q106 are alternatives, not a sequence. Confirm your route on your approval-to-test before investing weeks in celestial navigation you may not be assigned.
Chart Plot and Navigation Problems (Q107-Q109)
Domain 8: Q107 Chart Plot
Q107: Working the Chart
Q107 is the hands-on plotting module. It tests piloting, chart fixes and dead reckoning, together with electronic navigation, instruments, aids and publications.
- Constructing fixes from bearings, ranges and combinations
- Dead reckoning and estimated positions, including set and drift
- Electronic navigation integrated with traditional plotting
- Correct use of instruments, aids to navigation and publications
This module is about accuracy and method under time pressure. Your plotting workflow, the order in which you apply variation, deviation, set and drift, matters as much as your knowledge.
Domain 9: Q108 Navigation Problems - Near Coastal
Q108: Voyage and Position Calculations
- Ocean track and Mercator sailing
- ETA, speed, RPM and fuel calculations
- Electronic navigation, piloting and chart problems
- Compass and tide calculations
Domain 10: Q109 Navigation Problems - Oceans
Q109: The Full Ocean Calculation Set
- Ocean track, middle-latitude, Mercator, great-circle and parallel sailing
- ETA, piloting, chart and dead reckoning problems
- Celestial work: Polaris, meridian, fixes and star selection
- Times of celestial phenomena, zone time, sunrise, sunset and twilight
- Compass azimuth and amplitude calculations
- Tide calculations
Q109 is the most computation-intensive module in the series, and it is Oceans-only. The Near Coastal route does not require it.
Why Not Every Candidate Sits All Ten
It is tempting to read a ten-domain list as a ten-exam gauntlet. That is not how the credential works. The route you qualify for, and the approval-to-test the USCG issues, determine your assigned modules.
- Near Coastal route: navigation theory comes from Q105 and problems from Q108; Q109 is not required.
- Oceans route: navigation theory comes from Q106, with the Oceans problem set in Q109.
- Shared modules: Q100 through Q104 and Q107 form the common backbone of the deck, safety and chart-plot knowledge.
Sequencing the Modules in Your Preparation
Because the modules are unweighted, allocate time by personal weakness and by calculation load, not by an assumed percentage. One practical ordering, assuming an Oceans route, pairs conceptual modules with their problem counterparts:
Rules and deck foundation
- Q100 International versus Inland distinctions
- Q101 and Q102 including 33 CFR 164 and cargo stowage
Safety, then stability arithmetic
- Q103 emergency and lifesaving concepts, AMVER and IAMSAR
- Q104 trim, stability, damage and stress drills
Navigation theory and plotting
- Q105 or Q106 depending on route
- Q107 chart plot repetitions until your method is automatic
Navigation problems and review
- Q108 or Q109 calculation sets
- Mixed review across all assigned modules
For a fuller methodology, the study guide covers pacing, and the cheat sheet gives a compact review of must-know facts for the final days. To check your pass expectations honestly, read the passing score article and the pass rate discussion.
Key Takeaway
Do not schedule study by guessing at weights the NMC has not published. Schedule by module type: concepts first, calculations second, timed plotting last. Then verify with realistic practice on the main practice test site.
Frequently Asked Questions
The NMC's ONC01 chief mate series lists ten modules, Q100 through Q109. However, this is not ten mandatory modules for every candidate. Your approval-to-test determines which ones you are assigned.
No. The official module topics are unweighted, and the NMC does not publish percentage weights for them. Plan your time around module type and your own weak areas rather than assumed percentages.
Q105 is Navigation General for the Near Coastal route. Q106 is Navigation General for Oceans and adds nautical astronomy, celestial navigation, Polaris, star identification and selection, and meridian transit. They are route-related alternatives.
No. Q109 Navigation Problems - Oceans is an Oceans-only module. Near Coastal candidates use Q108, subject to the modules assigned on their USCG approval-to-test.
Q104 (stability and stress), Q107 (chart plot), Q108 and Q109 (navigation problems) are problem-solving modules. Q109 is the most extensive for Oceans candidates because it includes great-circle sailing, celestial fixes and twilight timing. Our domains overview and earnings analysis help put that effort in context.