- What This Credential Actually Is
- Who Issues It and How the Exam Works
- The Ten ONC01 Modules at a Glance
- Why Your Route Decides Your Modules
- Deck Modules: Rules, General, and Safety
- Navigation Modules: Piloting, Charts, and Problems
- What the Questions Feel Like
- Where This Endorsement Gets Used
- Sequencing Your Preparation
- Frequently Asked Questions
- USCG-CM-UNL here means National Chief Mate Unlimited, Oceans or Near Coastal, examined through the USCG National Maritime Center.
- The ONC01 exam draws from modules Q100 through Q109, but your assigned set depends on your route and approval to test.
- Q105 (Near Coastal) and Q106 (Oceans) are route alternatives; Q109 is Oceans-only content.
- Q103 and Q104 together cover safety theory and the stability, trim, and damage calculations you must perform.
What This Credential Actually Is
USCG-CM-UNL on this site refers to the National Chief Mate Unlimited, Oceans or Near Coastal endorsement. It is a United States Coast Guard mariner credential, not a vendor certificate and not an academic designation. The endorsement qualifies a licensed deck officer to serve as chief mate, the officer second in command who typically runs cargo operations, stability, deck maintenance, and the day-to-day management of the deck department, on vessels of unlimited tonnage.
The "Oceans or Near Coastal" wording matters. The endorsement is examined along one of two route lines, and that choice shapes which navigation modules you sit. If you are still comparing how this credential is described across the site, the related explainers What Is USCG-CM-UNL? and What Does USCG-CM-UNL Stand For? cover the naming in more detail.
Who Issues It and How the Exam Works
The governing body is the United States Coast Guard National Maritime Center (NMC). The NMC publishes the official examination topic lists for officer endorsements, including the Oceans or Near Coastal chief mate exam, designated ONC01. The module descriptions in this article come straight from that framework.
Several points about the structure are worth fixing in your mind early:
- The topics are unweighted. The NMC lists what each module covers but does not publish percentage weights, so you cannot "skip" a lightly weighted area. Treat every listed topic as fair game.
- Approval to test controls everything. The Coast Guard's approval determines which modules you are assigned. Do not build a study plan around a generic list of ten modules before you know what your approval actually says.
- Modules are discrete. Each module (Q100, Q101, and so on) is its own examination component with its own subject matter, which lets you plan and sit them in a deliberate order.
For the eligibility side of the process, including sea service and prerequisites, see USCG-CM-UNL Requirements. For what the money looks like, see USCG-CM-UNL Certification Cost.
The Ten ONC01 Modules at a Glance
The exam content is organized into ten module topics. The table summarizes each one and flags the route relationship.
| Module | Subject | Route Note |
|---|---|---|
| Q100 | Rules of the Road: International and Inland | Common to the framework |
| Q101 | Deck General Part I | Common to the framework |
| Q102 | Deck General Part II | Common to the framework |
| Q103 | Deck Safety | Common to the framework |
| Q104 | Deck Safety/Stability Problems | Common to the framework |
| Q105 | Navigation General: Near Coastal | Route alternative to Q106 |
| Q106 | Navigation General: Oceans | Route alternative to Q105 |
| Q107 | Chart Plot | Common to the framework |
| Q108 | Navigation Problems: Near Coastal | Near Coastal route |
| Q109 | Navigation Problems: Oceans | Oceans-only content |
A full domain-by-domain walkthrough lives in USCG-CM-UNL Exam Domains: Complete Guide to All 10 Content Areas. This article gives you the orientation; that one goes deeper on each area.
Why Your Route Decides Your Modules
The single most common misunderstanding about this credential is the belief that every candidate sits ten mandatory modules. They do not. Q105 and Q106 are route-related alternatives: the Near Coastal route points you to Q105, while the Oceans route points you to Q106. Likewise, Oceans-only material such as Q109 is not a universal requirement. A Near Coastal candidate is not expected to master great-circle sailing or celestial fixes simply because those topics appear elsewhere in the framework.
One more boundary to respect: eligibility rules written for Master credentials are not the rules for Chief Mate. Candidates sometimes read Master-level prerequisites in forum posts and assume they transfer. They do not belong in your Chief Mate preparation. If you want the Chief Mate rules specifically, start with the requirements guide linked above.
Deck Modules: Rules, General, and Safety
The first five modules form the deck-side backbone of the examination. Together they test whether you can run a watch legally, manage the ship and its people, and keep the vessel safe when things go wrong.
Q100: Rules of the Road, International and Inland
Covers the COLREGS and the Inland Rules together, along with safe watchkeeping. The challenge is not memorizing rule text in isolation but applying it to crossing, overtaking, and restricted-visibility situations, and knowing where the international and inland regimes diverge.
- Right-of-way and responsibility between vessels
- Lights, shapes, and sound signals
- Differences between International and Inland rules
Q101: Deck General Part I
A broad management-and-seamanship module. It spans maneuvering and handling, pilot stations, operation in rivers, estuaries, and shallow water, maritime law and credentialing, and shipboard management including personnel training.
- Ship handling in confined and shallow water
- Maritime law and credentialing responsibilities
- Shipboard management and crew training duties
Q102: Deck General Part II
Focuses on basic principles and watchkeeping, navigation safety requirements under 33 CFR 164, and cargo handling and stowage. The 33 CFR 164 material is regulatory and rewards careful reading of what equipment and procedures the regulation requires.
- Watchkeeping fundamentals
- 33 CFR 164 navigation safety requirements
- Cargo handling and stowage principles
Q103: Deck Safety
The widest safety module. It includes vessel construction, stability, trim, and damage concepts; grounding, refloating, collision, and temporary repairs; passenger safety; fire and abandoning ship; emergency steering; lifesaving rules and operation; and search and rescue, including AMVER and IAMSAR.
- Damage response, grounding, and refloating
- Fire, abandon ship, and lifesaving equipment rules
- Search and rescue frameworks (AMVER, IAMSAR)
Q104: Deck Safety/Stability Problems
This is the calculation counterpart to Q103. Expect to work trim, stability, damage stability, and stress problems. Where Q103 asks what you know, Q104 asks what you can compute under pressure.
- Trim and stability calculations
- Damage stability scenarios
- Stress calculations
For a structured approach to all of this content, see the USCG-CM-UNL Study Guide.
Navigation Modules: Piloting, Charts, and Problems
The remaining modules split between general navigation knowledge, chart work, and navigation calculations, with the route determining which versions you face.
Navigation General: Q105 versus Q106
Q105 (Near Coastal) covers piloting, distances, bearings, fixes, charts, and dead reckoning; instruments, aids, publications, and notices; magnetic and gyro compass work and error correction; azimuth, amplitude, and terrestrial fixes; and meteorology, weather, ocean currents, reports, tides, and safe watchkeeping.
Q106 (Oceans) includes the relevant piloting, chart, dead reckoning, aids, instruments, publications, compass, weather, tides, and watchkeeping material, and then adds the celestial layer: nautical astronomy, celestial navigation, Polaris, fixes, star identification and selection, and meridian transit.
Q107: Chart Plot
Chart Plot is hands-on. It covers piloting, chart fixes, and dead reckoning alongside electronic navigation, instruments, aids, and publications. Speed and accuracy with plotting tools matter as much as theory here.
Navigation Problems: Q108 versus Q109
Q108 (Near Coastal) concentrates on ocean track and Mercator sailing, ETA, speed, RPM, and fuel calculations, electronic navigation and piloting, chart and compass work, and tide calculations.
Q109 (Oceans) is the heaviest calculation module: ocean track, middle-latitude, Mercator, great-circle, and parallel sailing; ETA, piloting, chart work, and dead reckoning; celestial, Polaris, meridian, fixes, and star selection; times of celestial phenomena, zone time, sunrise, sunset, and twilight; compass azimuth and amplitude; and tide calculations.
What the Questions Feel Like
The module descriptions tell you what the exam is really testing. Some modules (Q100, Q101, Q102, Q103) lean toward regulatory and knowledge-based content: rules, management duties, safety systems, and procedures. Others (Q104, Q107, Q108, Q109) are working-problem modules where you produce an answer from given data, whether that is a trim moment, a plotted fix, an ETA, or a sailing distance.
That split suggests two different kinds of preparation. Knowledge modules reward reading the underlying sources carefully, including the rules text and 33 CFR 164. Problem modules reward repetition: you need to work enough examples that the procedure becomes automatic. To calibrate how demanding this is overall, read How Hard Is the USCG-CM-UNL Exam?, and for scoring thresholds see USCG-CM-UNL Passing Score. If you want a quick reference for last-minute review, the USCG-CM-UNL Cheat Sheet condenses the must-know facts.
For realistic, scenario-style repetition on the knowledge side, the USCG-CM-UNL practice tests are built around these module topics.
Where This Endorsement Gets Used
An unlimited chief mate endorsement is the credential that lets a deck officer fill the second-in-command role on large vessels. In practice that means the kinds of operators that run sizeable ocean-going or coastal tonnage: commercial shipping companies, tanker and cargo operators, offshore and energy-support fleets, government and research vessels, and cruise and passenger operations. The Oceans or Near Coastal distinction matters when matching the endorsement to a trade pattern, since it reflects the type of waters the officer is qualified for.
Because compensation varies widely with vessel type, trade, rotation, and employer, this article does not cite figures. For earnings context, see the USCG-CM-UNL Salary Guide and the career-oriented USCG-CM-UNL Jobs page. If you are weighing whether the investment of time and money makes sense, Is the USCG-CM-UNL Certification Worth It? walks through the reasoning.
Sequencing Your Preparation
Because the modules differ so much in character, ordering your study by module type is more useful than studying everything evenly. Here is a sample sequence, assuming your approval confirms the modules named. Adjust it to your actual assignment.
Rules and Regulatory Foundations
- Q100: work COLREGS and Inland Rules side by side, noting every divergence
- Q102: read 33 CFR 164 requirements closely
Safety Knowledge, Then Calculations
- Q103: construction, damage, fire, abandon ship, lifesaving, and AMVER/IAMSAR
- Q104: start stability and trim problems immediately after the theory, while it is fresh
Navigation by Your Route
- Q105 or Q106 as assigned, then Q107 chart plotting drills
- Q108 or Q109 problem sets, matched to your route
Management and Integration
- Q101: maneuvering, shallow-water handling, law, and shipboard management
- Mixed review across all assigned modules
The logic: regulatory reading first builds vocabulary used everywhere; safety theory is paired with its calculation module so the concepts and the math reinforce each other; and the calculation-heavy navigation work gets repeated problem practice rather than passive reading. Exam scheduling windows and deadlines are covered in USCG-CM-UNL Exam Dates, and a broader look at readiness is in USCG-CM-UNL Pass Rate.
Key Takeaway
Pair each knowledge module with its related problem module: Q103 with Q104, and Q105 or Q106 with Q107 and the matching problems module. Concepts stick when you immediately apply them in calculation.
Frequently Asked Questions
No. The ten modules (Q100 through Q109) describe the full ONC01 topic framework, but your USCG approval to test determines which are assigned. Q105 and Q106 are route alternatives, and Oceans-only Q109 is not required of every candidate.
The United States Coast Guard National Maritime Center governs the credential and publishes the official module topics for the Oceans or Near Coastal chief mate examination.
The official ONC01 module topics are listed without weights. Because no weighting is published, treat all listed topics in your assigned modules as testable rather than guessing at emphasis.
Q103 is Deck Safety, covering construction, stability concepts, emergencies, lifesaving, and search and rescue. Q104 is the problem-solving counterpart, covering trim, stability, damage stability, and stress calculations.
No. Master-only eligibility rules are separate and should not be imported into Chief Mate preparation. Confirm your own requirements and approval-to-test details instead, and see the USCG-CM-UNL Certification overview for more context.