- What Pass-Rate Data Actually Exists for This Exam
- What You Are Actually Taking: Modules, Not One Exam
- Great Lakes and Inland vs. Inland-Only Routes
- Where Candidates Tend to Struggle, Module by Module
- How to Read Pass-Rate Claims Without Being Fooled
- Sequencing Your Modules by Difficulty
- Who Uses This Endorsement
- Frequently Asked Questions
- No population-wide pass rate for National Master 500/1600 GL and Inland is established by the published NMC materials.
- The Great Lakes and Inland route uses six modules: Q100, Q320, Q321, Q322, Q323 and Q324.
- The Inland-only route uses five modules and swaps in Q100 or Q300, with no Q324.
- Your own NMC approval to test, not a forum post or a statistic, defines which modules you sit.
What Pass-Rate Data Actually Exists for This Exam
Candidates searching for a pass rate for the National Master 500/1600 GL and Inland endorsement usually want one clean number: the percentage of people who pass on the first attempt. This article will not invent one, because the sources reviewed do not publish one. The United States Coast Guard National Maritime Center (NMC) publishes module lists, topic matrices and its examination guide. It does not publish a population-wide pass rate for this credential in the materials we reviewed.
That absence matters. Any site quoting a precise percentage for this endorsement is either borrowing a figure from a different credential or making it up. Several unrelated certifications share similar-looking acronyms, and their statistics do not transfer. What you can do instead is understand the structure of the testing, identify where the real difficulty sits, and prepare in proportion to it. For a broader look at difficulty, see How Hard Is the NM51GI Exam? Complete Difficulty Guide 2026.
What You Are Actually Taking: Modules, Not One Exam
The first thing to correct is the idea of a single exam with a single pass rate. The NMC organizes the national Master 500/1600 GRT examination for Great Lakes and Inland waters under the GLI03 scope as a set of separate modules. Each module is its own test with its own subject area. A candidate can pass some and fail others, and this is why "pass rate" is a slippery concept here. A pass rate for which module? For which route? On which attempt?
The published module headings, corroborated by current NMC matrices, are:
- Q100: Rules of the Road, Inland and International
- Q300: Rules of the Road, Inland only (the restricted-route alternative to Q100)
- Q320: Deck General
- Q321: Deck Safety
- Q322: Navigation General, Great Lakes and Inland
- Q323: Navigation Problems, Chart Plot
- Q324: Great Lakes Topics, for the Great Lakes-and-Inland route only
Our NM51GI Exam Domains guide walks through each content area in more depth. The important point here is that these are issuer-published examination modules, which this site organizes as unweighted, route-aware preparation groups. No percentage weights are established for them, and no single overall question count or duration is established for the whole set.
Great Lakes and Inland vs. Inland-Only Routes
The number of modules you face depends on the route on your endorsement. The exact full-route module sets are below.
| Route | Modules | Count | Notes |
|---|---|---|---|
| Great Lakes and Inland | Q100, Q320, Q321, Q322, Q323, Q324 | 6 | Includes Great Lakes Topics (Q324) |
| Inland | Q100 OR Q300, Q320, Q321, Q322, Q323 | 5 | No Q324; Q100 and Q300 are alternatives |
Two traps appear constantly in candidate discussion. The first is counting Q100 and Q300 together. They are alternatives, not simultaneous requirements, so the Inland route is five modules, not six. The second is the reverse mistake: dropping Great Lakes Topics from a Great Lakes route and then double-counting Rules modules to reach an apparent six. The correct Great Lakes and Inland set is the six listed above, with Q324 present.
Raise-of-grade, upgrade and route-extension modules are separate from the full original set. For example, Q326 (Navigation and Deck General/Safety) is a distinct module for towing-to-Master under 500 raise-of-grade candidates. The guide also lists Inland-to-Great Lakes-and-Inland extensions (Q324, and Q100 where a COLREGS limitation applies) separately. These are not additional domains of the full original exam, so they should not be folded into any pass-rate reasoning. For the eligibility side of this, see NM51GI Requirements 2026: Eligibility, Prerequisites & How to Qualify.
Where Candidates Tend to Struggle, Module by Module
Because no official pass data exists, the most honest analysis is qualitative: which modules demand the most from a typical mariner, and why. The following reflects the nature of the content, not measured failure statistics.
Domain 1: Rules of the Road (Q100 / Q300)
Rules questions reward precision. You need to know the difference between Inland and International rules where they diverge, and which module applies to your route.
- Q100 covers Inland and International; Q300 is Inland-only.
- Applicants with a COLREGS limitation may be assigned Q100 on an extension.
- Light, shape and sound-signal recall is a common stumbling block.
Domain 2: Deck General (Q320)
This module covers broad seamanship and vessel-operation knowledge. Breadth is the challenge: many small topics rather than one deep one.
- Expect questions spanning general deck knowledge rather than a single skill.
- Reading the published NMC topic matrix helps you spot gaps early.
Domain 3: Deck Safety (Q321)
Safety questions test regulatory and practical knowledge of keeping a vessel and crew safe. Candidates with strong sea time sometimes underestimate the regulatory phrasing.
- Study the module's topic headings against your own experience to find blind spots.
Domain 4: Navigation General (Q322)
This module covers the published navigation general topics for Great Lakes and Inland waters. It is knowledge-heavy and rewards systematic review.
- Published topics include piloting, compass error and meteorology/oceanography.
Domain 5: Navigation Problems, Chart Plot (Q323)
Chart plotting is a working skill, not a memory exercise. Accuracy under time pressure comes only from repeated worked problems.
- Practice plotting, course and distance work, and compass-error corrections by hand.
- Small arithmetic or plotting slips can cascade into wrong answers.
Domain 6: Great Lakes Topics (Q324)
Applies to the Great Lakes-and-Inland route only. The published topics include maneuvering and handling (including ice), stability, construction and damage control, and cargo handling.
- Candidates from purely Inland backgrounds often find ice and Great Lakes conditions unfamiliar.
For a one-page recap of the highest-yield facts across these areas, the NM51GI Cheat Sheet is a useful companion.
How to Read Pass-Rate Claims Without Being Fooled
Since you will encounter pass-rate claims anyway, here is a checklist for evaluating them.
- Ask which credential. The same acronym is used by unrelated certifications. A figure for a different credential says nothing about the USCG National Master 500/1600 GL and Inland endorsement.
- Ask which module and route. A claim about "the exam" ignores that this is a set of separate modules, and that the set differs by route.
- Ask for a source. A real statistic traces back to an issuer or a documented survey. The NMC pages we reviewed do not provide one.
- Ask about attempts. Modules can be retaken, so first-attempt and eventual success are very different measures.
- Check the date. The examination guide referenced in our sources is the published regulations-effective March 24, 2014 document, not a newly issued 2026 blueprint, though current indexed NMC matrices corroborate the same module headings.
Key Takeaway
Treat the lack of a published pass rate as information, not a gap to fill with rumor. Your best predictor of success is how well your preparation matches the specific modules on your approval to test. See NM51GI Passing Score 2026 for what is and is not established about scoring.
Sequencing Your Modules by Difficulty
This is the one place where scheduling advice belongs, and it is tied directly to the modules rather than to generic study technique. Because modules are separate tests, you can plan the order. A sensible approach front-loads the skill-based work and saves broad-recall modules for when your general knowledge has had time to settle.
Q323 Chart Plot and Q322 Navigation General
- Work plotting problems by hand until corrections become automatic.
- Review piloting, compass error and meteorology topics alongside.
Q100 or Q300 Rules of the Road
- Confirm from your approval which Rules module you sit.
- Drill signals, lights and right-of-way situations.
Q320 Deck General and Q321 Deck Safety
- Use the NMC topic matrix as a checklist against your experience.
Q324 Great Lakes Topics (Great Lakes route only)
- Focus on ice maneuvering, stability, damage control and cargo handling.
The logic: chart plotting and navigation calculations decay quickly without practice, so they get early and repeated attention. Rules content is high-stakes and benefits from a dedicated block. Great Lakes Topics only apply to one route, so Inland-only candidates simply skip that final week. For a fuller plan, see the NM51GI Study Guide 2026, and you can test yourself on the main practice test site as you go.
Who Uses This Endorsement
A national Master 500/1600 GRT endorsement for Great Lakes and Inland waters qualifies a mariner to serve as master of vessels within the stated tonnage and route limits. In practice, that points toward employers operating on the Great Lakes, rivers and other inland waterways: towing and barge operators, passenger and excursion vessel operators, and other commercial fleets working those waters. We do not cite salary figures here because none are established in our source packet. For the career angle, our NM51GI Jobs overview and the ROI analysis cover this in more detail.
On cost and scheduling, the same caution applies: no current fees are established by our sources, so check the NMC directly before budgeting. Our cost breakdown and exam dates article explain what to verify and where.
Frequently Asked Questions
No population-wide pass rate is established by the NMC materials we reviewed. Be skeptical of any specific percentage you see quoted, since it may belong to a different credential that shares the NM51GI acronym.
On the full Great Lakes and Inland route, the module set is Q100, Q320, Q321, Q322, Q323 and Q324, which is six. On the Inland route it is Q100 or Q300, plus Q320, Q321, Q322 and Q323, which is five. Your NMC approval to test defines your actual assignment.
No. Q100 and Q300 are alternative Rules of the Road modules, not simultaneous requirements. Which one applies depends on your route and any COLREGS limitation on your approval.
Q323 Navigation Problems, Chart Plot, because it is a hands-on skill that improves only with repeated worked problems. Use the NMC's published topic matrices to find your weakest areas in the other modules.
No. Q326, Navigation and Deck General/Safety, is a separate module for towing-to-Master under 500 raise-of-grade applicants. It is not an additional domain of the full original exam.
For a general introduction to the credential, start with What Is NM51GI?, and when you are ready to test your knowledge, head to the NM51GI practice test. This material is independent exam preparation and does not imply issuer endorsement.