- What National Master 100 GL and Inland Actually Covers
- How the Five Preparation Groups Fit Together
- Domain 1: Rules of the Road (Q100 or Q300)
- Domain 2: Deck General (Q347)
- Domain 3: Deck Safety (Q348)
- Domain 4: Navigation General, Great Lakes and Inland (Q349)
- Domain 5: Navigation Problems, Chart Plot (Q350)
- Where Q352 Fits: The Raise-of-Grade Module
- Great Lakes Versus Inland: Route Details That Change Your Prep
- Sequencing Your Preparation by Domain
- Frequently Asked Questions
- NM1GI here means National Master 100 GL and Inland, governed by the U.S. Coast Guard National Maritime Center.
- Preparation breaks into five groups: Rules (Q100 or Q300), Deck General Q347, Deck Safety Q348, Navigation General Q349, Chart Plot Q350.
- Your approval to test from the NMC controls which modules, which Rules route, and any credit you receive.
- Q352 is a separate raise-of-grade module, not a sixth universal group or a second Rules subject.
What National Master 100 GL and Inland Actually Covers
National Master 100 GL and Inland is a Coast Guard mariner credential for the master of vessels under 100 gross register tons operating on the Great Lakes and inland waters. The examination program is administered by the United States Coast Guard National Maritime Center (NMC), and the route is listed in the NMC's examination catalog under the code GLI06, titled Master or Mate less than 100 GRT. If you have seen the NM1GI acronym attached to other credentials elsewhere, set that aside: everything in this guide concerns the Coast Guard deck-officer route and nothing else.
The first thing to understand is that this is not a single commercial test with a fixed blueprint. The NMC organizes deck examinations into modules, each identified by a Q-number, and the set of modules you actually sit depends on your application, your route, and the approval to test the NMC issues to you. That is why this guide describes five route-aware preparation groups rather than five official exam sections with published percentages. The NMC does not publish percentage weights for these groups in the materials this site relies on, so any claim that one group is worth a specific share of your result would be invented.
The source material behind this article is the NMC's published module-topic index for GLI06, along with the NMC Examination Guide whose regulations are effective March 24, 2014. That guide remains a useful reference, but it should be used alongside the current published module-topic index and your own approval to test. It is not a new 2026 universal exam specification, and this article does not present it as one.
How the Five Preparation Groups Fit Together
The five groups below are a preparation framework built from the NMC's published topic catalog. Counting the route-specific Rules choice once (either Q100 or Q300, never both), the full-route preparation picture looks like this:
| Group | Module | Core Subject Areas |
|---|---|---|
| 1 | Rules of the Road: International and Inland (Q100) OR Inland (Q300) | Watchkeeping, COLREGS, Inland Navigational Rules |
| 2 | Deck General (Q347) | Seamanship, vessel handling, maritime law, shipboard management |
| 3 | Deck Safety (Q348) | Stability, firefighting, emergencies, communications and signals |
| 4 | Navigation General: Great Lakes and Inland (Q349) | Piloting, compass, aids to navigation, meteorology, tides and currents |
| 5 | Navigation Problems: Chart Plot (Q350) | Chart-plotting problems: fixes, bearings, distance off, dead reckoning |
Two structural points deserve emphasis. First, the Rules group is a choice made according to your approved route, so you prepare for one Rules module, not two. Second, Navigation General (Q349) and Chart Plot (Q350) overlap in subject matter but not in format: Q349 tests the knowledge, while Q350 tests whether you can execute the plotting work. Candidates who treat them as one block of "navigation" tend to under-practice the hands-on plotting skill.
For a broader look at how demanding this combination is, see How Hard Is the NM1GI Exam? For the logistics of qualifying before you ever reach the exam room, the NM1GI requirements guide covers eligibility and prerequisites.
Domain 1: Rules of the Road (Q100 or Q300)
The Rules module is the one place where your route directly changes which exam you take. The NMC lists Rules of the Road: International and Inland (Q100) or Inland (Q300), according to the approved route. The published topic headings are Watchkeeping, COLREGS, and Inland Navigational Rules.
Rules of the Road (Q100 / Q300)
This domain tests whether you can apply the steering and sailing rules, lights, shapes, and sound signals to realistic encounters, and whether you know which rule set governs where you are operating.
- COLREGS: the International Regulations for Preventing Collisions at Sea, which matter for the international-and-inland (Q100) route.
- Inland Navigational Rules: the rule set governing inland waters, which is the core of the Q300 route and an essential part of Q100.
- Watchkeeping: the Rules-related watchkeeping principles listed under this module, including lookout and safe-speed judgment.
The practical difficulty is not memorizing rule numbers; it is rapid discrimination between near-identical situations. A question may hinge on whether you are the stand-on or give-way vessel, whether a light configuration indicates a vessel restricted in her ability to maneuver, or which sound signal is correct for a given intention. Do not conflate the two rule sets: where the international and inland rules differ in wording or signals, those differences are exactly where careful test-writers aim.
Domain 2: Deck General (Q347)
Deck General is the broadest seamanship-and-operations module in the published catalog, and it is where hands-on mariners often feel most at home while still being surprised by the regulatory and management topics. The catalog groups its content as follows.
Seamanship and Vessel Handling
These topics test practical judgment about how a vessel behaves and how to work lines and gear.
- Seamanship and marlinspike seamanship
- Purchases, blocks, and tackle
- Vessel maneuvering and handling, including handling in rivers and estuaries
- Maneuvering in shallow water and interaction with a bank or passing ship
- Berthing and unberthing
- Anchoring and mooring, dragging of anchors, and clearing fouled anchors
- Turn circle, pivot point, advance and transfer, and wake reduction
Heavy Weather and Lifeboat Maneuvering
Two topics here carry route significance: Heavy Weather Operations and Maneuvering for Launching of Lifeboats and Liferafts in Heavy Weather. In the NMC table, these are marked with a footnote identifying them as Great Lakes-specific. Whether they appear for you depends on your approved route, so check your approval to test rather than assuming they are in or out.
Law, Management, and Documentation
This is the portion of Deck General that surprises candidates who prepared only for seamanship.
- Maritime law and national maritime law
- Credentialing of seamen
- Shipboard management and training, including ship sanitation
- Vessel alteration, repair, and hot work
- Safety and ship's business
- Certificates and documents required
A useful way to study this module is to separate "how the boat behaves" from "what the paperwork and law require." Pivot point and turn-circle questions reward physical intuition; certificates, documents, and credentialing questions reward careful reading of the regulatory framework. Neither substitutes for the other.
Domain 3: Deck Safety (Q348)
Deck Safety collects the topics where an error has the most serious real-world consequences: stability, fire, emergencies, and signaling. The published topic list is long and organized into several clusters.
Stability, Construction, and Damage Control
- Principles of vessel construction
- Trim and stability
- Watchkeeping basic principles
Vessel Power Plants and Fire
- Small engine operations and maintenance
- Fire prevention and firefighting appliances
- Organization of fire drills
- Classes and chemistry of fire
- Firefighting systems and basic firefighting and prevention
Emergency Procedures
The emergency list reads like a master's contingency checklist, and questions tend to test sequencing and priorities.
- Collision and temporary repairs
- Passenger and crew safety in emergencies
- Fire or explosion
- Abandon-ship procedures
- Rescuing survivors from a ship or aircraft in distress
- Man-overboard procedures
- Emergency towing
Communications and Signals
Storm, wreck, distress, and special signals appear under the communications heading. These are factual-recall items, so flashcard-style practice pays off here more than almost anywhere else in the program.
Because this module covers both technical principles (stability, fire chemistry) and procedural judgment (abandon ship, man overboard), it rewards candidates who can explain not just what to do but why the sequence matters. The NM1GI cheat sheet is a handy place to consolidate the signal and fire-class facts once you have learned them properly.
Domain 4: Navigation General, Great Lakes and Inland (Q349)
Navigation General (Q349) is the knowledge-heavy half of the navigation pair, tailored to Great Lakes and inland operations. Its published topics span position determination, instruments, publications, compasses, and environmental factors.
Navigation and Position Determination
- Piloting, distance off, and bearing problems
- Fix or running fix
- Chart navigation and dead reckoning
- Electronic navigation
- Instruments and accessories
Aids, Charts, and Publications
- Aids to navigation
- Charts, navigation publications, and Notices to Mariners
Compass Work
- Principles of the magnetic compass
- Magnetic compass error and correction
- Determination of compass error, including terrestrial observation
Meteorology, Oceanography, Tides, and Currents
- Characteristics of weather systems
- Weather charts and reports
- Tides and tidal currents
Compass error is the classic stumbling block in this module. Variation, deviation, and the conversion between true, magnetic, and compass headings generate a steady supply of calculation questions, and a single sign error propagates through the whole answer. Practice these conversions until the direction of each correction is automatic.
Key Takeaway
Q349 and Q350 draw on overlapping topic lists, but they test different skills. Q349 checks that you understand piloting, compass work, and publications; Q350 checks that you can actually construct the answer on a chart. Study the concepts first, then drill the execution.
Domain 5: Navigation Problems, Chart Plot (Q350)
Chart Plot (Q350) is the practical plotting module. The NMC's listed topics are piloting, distance off, bearing problems, fix or running fix, chart navigation, dead reckoning, electronic navigation, instruments and accessories, aids to navigation, and charts, navigation publications, and Notices to Mariners. In other words, it is the applied counterpart to the position-determination half of Q349.
Success here depends on technique and accuracy rather than recall. Typical skill areas include laying off courses, applying set and drift, working a running fix, solving a distance-off problem, and reading aids to navigation correctly from the chart. Small plotting errors, such as a misread scale, an incorrect compass correction, or a transposed bearing, can place you in the wrong position by a meaningful margin.
The pass threshold for this credential is its own subject; see NM1GI Passing Score for what the published requirements say, and NM1GI Pass Rate for how to interpret outcome data responsibly.
Where Q352 Fits: The Raise-of-Grade Module
You may see Q352, Navigation and Deck General/Safety, mentioned alongside GLI06. The NMC lists it as a separate module in the route's catalog, and the NMC has published a dedicated Q352 document for it. It is used for a raise-of-grade route, and it should not be confused with a universal sixth exam group for everyone pursuing a full original credential.
| Question | Answer |
|---|---|
| Is Q352 a sixth group for every candidate? | No. It is a separately listed raise-of-grade route module. |
| Is Q352 a second Rules subject? | No. Rules remains a single Q100 or Q300 choice. |
| Who decides if Q352 applies to you? | Your NMC approval to test, based on your application and route. |
If you are applying for a full original credential, build your plan around the five groups above and confirm with your approval to test whether Q352 is relevant to you. If you are pursuing a raise of grade, read the NMC's Q352 document directly and follow what your approval specifies.
Great Lakes Versus Inland: Route Details That Change Your Prep
The "GL and Inland" in the credential name is not decoration. The NMC's published tables distinguish between topics that apply to Great Lakes-and-Inland versus Inland-only applicability, and some topics are flagged as Great Lakes-specific.
- Heavy Weather Operations and Maneuvering for Launching of Lifeboats and Liferafts in Heavy Weather (both in Deck General) carry the Great Lakes-specific footnote.
- The Rules module splits into Q100 (International and Inland) versus Q300 (Inland), according to your approved route.
- Navigation General is explicitly titled for Great Lakes and Inland (Q349).
The takeaway is that two candidates holding the same credential title may be preparing for slightly different topic sets. Do not copy another mariner's study list verbatim; reconcile it against your own approval to test. For fee and scheduling mechanics around your application, the certification cost breakdown and exam dates guide explain how to plan the administrative side.
Sequencing Your Preparation by Domain
Rather than a generic weekly template, the order below follows how the domains depend on one another. Adjust the pacing to your own sea time and weak areas; the point is the dependency logic, not the exact number of weeks.
Rules of the Road (Q100 or Q300)
- Confirm which Rules module your approval lists, then study only that rule set in depth.
- Build fluency with lights, shapes, and sound signals before attempting encounter scenarios.
- Rules knowledge supports the Watchkeeping topics that recur in Deck Safety.
Navigation General (Q349)
- Learn compass error and correction thoroughly, since Chart Plot depends on it.
- Cover aids to navigation, publications, and Notices to Mariners.
- Add meteorology, tides, and currents for the Great Lakes and inland setting.
Chart Plot (Q350)
- Apply Q349 concepts to timed plotting problems: fixes, running fixes, distance off.
- Practice with real tools until your method is repeatable.
Deck General (Q347) and Deck Safety (Q348)
- Pair vessel handling with heavy-weather and lifeboat-maneuvering topics if your route includes them.
- Review law, documents, and credentialing separately from seamanship.
- Finish with emergency procedures, firefighting, and signals.
This ordering puts the dependency-heavy navigation work in the middle, so the compass fundamentals are fresh when you start plotting, and saves the broad recall-heavy modules for the stretch before testing. For a fuller framework, see the NM1GI study guide, and when you are ready to test yourself against realistic questions, try the NM1GI practice tests and use the results to decide which group needs another pass.
Frequently Asked Questions
No percentage weights are published in the sources used for this guide. The five groups here are unweighted, route-aware preparation groups drawn from the NMC's published module-topic catalog, not a single common mandatory examination blueprint.
No. The Rules of the Road module is Q100 (International and Inland) or Q300 (Inland), according to your approved route. It counts once among the five groups.
No. Q352, Navigation and Deck General/Safety, is a separately listed raise-of-grade route module. Check your approval to test to see whether it applies to you.
In the NMC table, Heavy Weather Operations and Maneuvering for Launching of Lifeboats and Liferafts in Heavy Weather are marked with a footnote identifying them as Great Lakes-specific. Your route determines whether they apply to you.
The NMC Examination Guide referenced here reflects regulations effective March 24, 2014. Use it alongside the current NMC module-topic index and your individual approval to test; it is not a new 2026 universal specification. For career context after you qualify, see the NM1GI jobs and is it worth it guides.