- What This Cheat Sheet Covers (and What It Does Not)
- The Module Map: Q100 Through Q324
- Route Math: Why Five and Six Are Both Right
- Rules of the Road: Q100 and Q300
- Deck General and Deck Safety: Q320 and Q321
- Navigation General and Chart Plot: Q322 and Q323
- Great Lakes Topics: Q324
- Raise-of-Grade and Route-Extension Modules
- Counting Mistakes That Cost Candidates Time
- A Domain-Ordered Prep Sequence
- Frequently Asked Questions
- NM51GI is the National Master 500/1600 GL and Inland credential, governed by the U.S. Coast Guard National Maritime Center (scope GLI03).
- Great Lakes and Inland route: six modules (Q100, Q320, Q321, Q322, Q323, Q324). Inland route: five, with no Q324.
- Q100 and Q300 are alternatives, never simultaneous requirements. Do not count both toward your total.
- Your NMC approval to test, not a generic list, defines which modules you actually sit.
What This Cheat Sheet Covers (and What It Does Not)
This is a one-page-style review of the structural facts every National Master 500/1600 GL and Inland (NM51GI) candidate should have memorized before opening a single study chapter. The credential is administered through the United States Coast Guard National Maritime Center (NMC), and the exam scope code is GLI03. The NMC publishes its examination modules and topic matrices openly, so nothing here is secret; the value is in having the module map, route logic and topic list condensed into one place.
Just as important is what this sheet deliberately leaves out. The published materials reviewed for this article do not establish topic weighting percentages, a single overall question count or time limit, current fees, or any population-wide pass rate. If you see a site quoting those as hard facts for this credential, treat them skeptically. For the candidate-facing details that are discussed elsewhere, see our pieces on NM51GI certification cost and what the pass-rate data shows.
The Module Map: Q100 Through Q324
The NMC organizes the exam by module codes. For the full Master 500/1600 Great Lakes and Inland route, these are the codes that matter:
| Module | Subject | Applies To |
|---|---|---|
| Q100 | Rules of the Road: Inland and International | Great Lakes and Inland route; also Inland where a COLREGS limitation applies |
| Q300 | Rules of the Road: Inland only | Inland route, as the alternative to Q100 |
| Q320 | Deck General | Both routes |
| Q321 | Deck Safety | Both routes |
| Q322 | Navigation General: Great Lakes and Inland | Both routes |
| Q323 | Navigation Problems: Chart Plot | Both routes |
| Q324 | Great Lakes Topics | Great Lakes and Inland route only |
These six headings (with Q300 as the Inland-only Rules alternative) are the same six content areas explored in more depth in our complete guide to the NM51GI exam domains. They are best understood as unweighted, route-aware preparation groups. They tell you what to learn, not how many points each is worth.
Route Math: Why Five and Six Are Both Right
The most common confusion on this credential is the module count. Two statements are simultaneously true, and both belong on your cheat sheet:
- Great Lakes and Inland: Q100, Q320, Q321, Q322, Q323, Q324. That is six modules.
- Inland: Q100 or Q300, Q320, Q321, Q322, Q323. That is five modules, because Q324 is omitted.
The word "or" in the Inland line is doing real work. Q100 and Q300 are alternatives. A candidate sits one Rules module, not both. Likewise, the six-module Great Lakes and Inland route does not become "seven" by adding Q300, and you should never pad a total by counting alternative Rules or Navigation General modules together as simultaneous requirements.
Equally important, "six" is not a universal count of examinations for every applicant. Your individual module assignment comes from the NMC. Whether you are a first-time candidate or someone with prior credentials, the actual approval to test is the authority. For eligibility questions upstream of that approval, see NM51GI requirements and how to qualify.
Rules of the Road: Q100 and Q300
Domain 1: Rules of the Road (Inland and International)
The Rules module is the one that depends on your route restriction. Q100 covers Inland and International rules; Q300 covers Inland rules only and serves as the restricted-route alternative.
- Know which Rules module your approval to test names before you start studying.
- Where a COLREGS limitation applies on the Inland route, Q100 is listed separately in the published guide.
- Expect the content to center on navigation rules, lights, shapes, sound signals and right-of-way relationships.
Because Rules is the one module with an either/or choice, it is the first place a wrong assumption can cost you. A candidate who studies international-only material for a restricted Inland assignment, or the reverse, is spending time on the wrong module. Check the approval, then match your prep to it.
Deck General and Deck Safety: Q320 and Q321
Domain 2: Deck General (Q320)
Core deck seamanship and vessel-operations knowledge expected of a master of vessels under 500/1600 gross register tons.
- Study it as shared foundation material: it applies on both the Great Lakes and Inland and the Inland routes.
- Pair it with the stability, construction and cargo-handling concepts that the published topic list associates with the master-level modules.
Domain 3: Deck Safety (Q321)
Safety, emergency response and damage-control knowledge tied to the responsibilities of command.
- Treat damage control and emergency procedures as scenario knowledge, not recitation.
- Like Q320, it applies to both routes, so time invested here is never wasted regardless of your assignment.
These two modules are route-agnostic, which makes them the safest place to build early momentum. Whatever your final module list, Q320 and Q321 are on it.
Navigation General and Chart Plot: Q322 and Q323
Domain 4: Navigation General: Great Lakes and Inland (Q322)
The knowledge-based navigation module for this credential.
- Published topics associated with the master-level navigation modules include piloting, compass error, and meteorology and oceanography.
- Maneuvering and handling, including ice, appears in the published topic list, a reminder that Great Lakes operations carry seasonal hazards inland waters elsewhere do not.
Domain 5: Navigation Problems: Chart Plot (Q323)
The applied side of navigation: working problems on a chart rather than recalling facts.
- Plan to practice with actual plotting tools and charts, not just reading about the method.
- Compass error and piloting skills from Q322 feed directly into the plotting work here, so the two modules reinforce each other.
Note that Q322 and Q323 are distinct modules with different demands. One tests what you know; the other tests whether you can do the work under exam conditions. For a candid look at where candidates struggle, read how hard the NM51GI exam really is.
Great Lakes Topics: Q324
Domain 6: Great Lakes Topics (Q324)
Q324 is the module that separates the Great Lakes and Inland route from the Inland route. If your approval to test lists it, it is a full module requiring dedicated preparation. If your assignment is Inland only, you do not sit it.
- It is the reason the Great Lakes and Inland route runs to six modules while Inland runs to five.
- Do not omit it from your plan on the Great Lakes route, and do not attempt to offset its absence by double-counting Rules modules on the Inland route.
Key Takeaway
Q324 is the only module that exists on one route and not the other. If you remember nothing else about route math, remember that Great Lakes Topics is the difference between six and five.
Raise-of-Grade and Route-Extension Modules
The published materials also reference modules that sit outside the full-original-exam list above, and mixing them in is a frequent source of confusion.
- Q326, Navigation and Deck General/Safety: a separate module for the towing-to-Master-under-500 raise-of-grade path. It is not a seventh module on the full-route lists.
- Inland-to-Great-Lakes/Inland route extension: the guide lists Q324 (and Q100 where a COLREGS limitation applies) separately for candidates extending an Inland credential.
| Situation | How to Think About It |
|---|---|
| Full original Great Lakes and Inland | Six modules: Q100, Q320, Q321, Q322, Q323, Q324 |
| Full original Inland | Five modules: Q100 or Q300, Q320, Q321, Q322, Q323 |
| Towing to Master under 500 raise of grade | Q326 as a separate module; not an added domain on the full-route lists |
| Inland extended to Great Lakes and Inland | Q324, plus Q100 where a COLREGS limitation applies, listed separately |
The principle: upgrade, raise-of-grade and route-extension modules are not additional domains stacked onto the full original exam. They are separate paths that the NMC assigns individually. If you are weighing which path fits your career, our ROI analysis of the NM51GI certification and the salary guide put the decision in context.
Counting Mistakes That Cost Candidates Time
- Adding Q100 and Q300 together. They are alternatives. One applies to you.
- Dropping Q324 on a Great Lakes route. It is required for that route's full module set.
- Treating "six" as universal. The six-module list is for the full Great Lakes and Inland route; Inland is five.
- Folding Q326 into the full-route count. It is a separate raise-of-grade module.
- Quoting weights or a single question count. The reviewed sources do not establish percentages, an overall question count, or an overall duration. Rely on your NMC approval and published matrices, not forum numbers.
- Studying from the wrong blueprint. The guide referenced here is the March 24, 2014 published document, corroborated by current NMC matrices; confirm module headings against the NMC pages before building a plan.
A Domain-Ordered Prep Sequence
Rather than a generic schedule, sequence your preparation by how the modules depend on each other. This is the only structured planning section in this sheet, and it is tied to the module map above.
Confirm and Foundation
- Read your approval to test and write down your exact module list.
- Start Q320 Deck General, since it applies to every route.
Safety and Rules
- Work through Q321 Deck Safety.
- Begin your assigned Rules module (Q100 or Q300), not both.
Navigation Knowledge
- Cover Q322 topics: piloting, compass error, meteorology and oceanography.
- Review maneuvering and handling, including ice.
Plotting and Great Lakes
- Drill Q323 chart-plot problems with real tools.
- If assigned, study Q324 Great Lakes Topics; if Inland only, extend plotting practice instead.
For a fuller methodology, see the NM51GI study guide, and when you are ready to test your recall, run timed sets on our NM51GI practice test platform. Practice questions on that site are original study aids and do not reproduce issuer exam content or imply issuer endorsement. Scheduling logistics are covered in NM51GI exam dates and testing windows.
Frequently Asked Questions
The Great Lakes and Inland route has six: Q100, Q320, Q321, Q322, Q323 and Q324. The Inland route has five, using Q100 or Q300 for Rules and omitting Q324. Your individual set is whatever the NMC assigns in your approval to test.
No. They are alternatives. Q100 covers Inland and International rules, while Q300 is the Inland-only option for restricted routes. Alternative modules are never simultaneous requirements.
No. Q326 Navigation and Deck General/Safety is a separate raise-of-grade module for the towing-to-Master-under-500 path, not an extra domain on the full-original-exam lists.
The sources reviewed for this sheet do not establish topic percentages, a single overall question count or duration, current fees, or a population pass rate. Confirm those details directly with the NMC. For discussion of scoring, see NM51GI passing score.
Start with What Is NM51GI? for the credential overview and NM51GI jobs for employment context, then return to this sheet as a quick structural reference before your exam.