- What NM2GI Actually Is
- Who Issues It and What It Authorizes
- How the Exam Is Built: Modules, Not One Big Test
- The Five Preparation Groups in Detail
- Q100 vs. Q300: An Either/Or Choice
- Q345 and Q346: Modules That Belong to Other Routes
- Why Your Approval to Test Is the Final Word
- Where the Credential Gets Used
- Sequencing Your Preparation
- Frequently Asked Questions
- NM2GI is National Master 200 GL and Inland, issued through the U.S. Coast Guard National Maritime Center under scope GLI05.
- GLI05 covers Master or Mate of vessels less than 200 GRT on Great Lakes and Inland waters.
- The full-route exam uses five module groups; Q100 and Q300 are alternatives, never both.
- Chart Plot (Q343) is required in the full-exam structure and cannot be skipped.
What NM2GI Actually Is
NM2GI stands for National Master 200 GL and Inland. It is a U.S. mariner credential pathway for people who intend to serve as Master or Mate aboard vessels of less than 200 gross register tons (GRT) operating on the Great Lakes and inland waters. On this site, NM2GI means that credential and nothing else. If you have seen the same letters attached to other certifications elsewhere, set those aside: nothing about them applies here.
If you are new to the topic, a few related explainers cover the naming angle from different directions, including what NM2GI stands for and the meaning of NM2GI. This article focuses on what the credential is in practice: who runs it, how the examination is organized, and what a candidate actually has to learn.
Who Issues It and What It Authorizes
The governing body is the United States Coast Guard National Maritime Center (NMC). The NMC evaluates mariner applications, approves candidates to test, and publishes the examination modules and topic matrices that define what each exam covers. The examination scope for this credential is coded GLI05, which the NMC describes as Master or Mate less than 200 GRT.
That wording matters. This is a Master or Mate endorsement for smaller vessels, not an unlimited-tonnage license and not an entry-level operator credential. It sits in the deck-officer lane: navigation, vessel handling, safety management, and rules compliance for vessels in the sub-200 GRT class working on Great Lakes and inland routes.
How the Exam Is Built: Modules, Not One Big Test
The most common misunderstanding about NM2GI is picturing a single exam with one question count and one time limit. The NMC structures the examination as a set of modules, each identified by a Q-number. Which modules you sit depends on your route and the type of application you file.
For the full-route pathway, the published module sets are:
| Route | Modules | Count |
|---|---|---|
| Great Lakes and Inland | Q100, Q340, Q341, Q342, Q343 | 5 modules |
| Inland | Q100 or Q300, Q340, Q341, Q342, Q343 | 5 modules |
This site organizes those modules into five unweighted, route-aware preparation groups. "Unweighted" is deliberate: the sources reviewed do not establish percentage weightings, a single overall question count, or a single overall duration, so any article claiming exact percentages for NM2GI is guessing. And "route-aware" means the groups flex with your route rather than representing a universal list of exams every applicant must pass.
For a domain-by-domain walkthrough, see NM2GI Exam Domains 2026: Complete Guide to All 5 Content Areas.
The Five Preparation Groups in Detail
Domain 1: Rules of the Road, Inland and International (Q100)
The navigation-rules group. For Great Lakes and Inland candidates this is Q100. Inland-only candidates on an applicable restricted route may instead use Q300.
- Steering and sailing rules, including vessel-to-vessel situations such as crossing, overtaking, and meeting
- Lights, shapes, and sound signals
- Understanding how Inland and International rules differ, since Q100 spans both
- Applying rules to scenarios, not just reciting definitions
Domain 2: Deck General (Q340)
Core seamanship and vessel knowledge for a deck officer.
- General deck operations and vessel familiarity
- Practical seamanship concepts that underpin safe handling
- The working vocabulary of the deck department
Domain 3: Deck Safety (Q341)
Safety management and emergency preparedness from the Master or Mate perspective.
- Safety equipment and its proper use
- Emergency response responsibilities
- Safe operating practices aboard the vessel
Domain 4: Navigation General, Great Lakes and Inland (Q342)
The broad navigation theory group for Great Lakes and inland operations.
- Navigation aids, publications, and how to use them
- Piloting concepts specific to Great Lakes and inland waters
- Weather, tides, and currents as they affect passage planning
Domain 5: Navigation Problems, Chart Plot (Q343)
The hands-on chart-work group. In the full-exam structure, Chart Plot is required and must not be omitted from your preparation.
- Plotting courses, positions, and fixes on a chart
- Working navigation problems accurately and methodically
- Precision under time pressure, since small plotting errors compound
One practical observation: Q343 is the group where arithmetic and chart discipline matter more than memorization. Candidates who treat it as "just another reading module" tend to find it the hardest to catch up on late. If you are weighing relative difficulty across the groups, How Hard Is the NM2GI Exam? Complete Difficulty Guide 2026 goes deeper.
Q100 vs. Q300: An Either/Or Choice
The five groups can look like six modules if you list every Q-number you encounter. They are not. Q100 and Q300 are alternatives, not two extra domains.
- Great Lakes and Inland uses Q100.
- Inland may use Q300 when the applicable COLREGS limitation is accepted.
Accepting a COLREGS limitation is a real tradeoff. Q300 is the inland-only rules module, which narrows your exam preparation but also narrows what the resulting endorsement is built around. Decide this consciously with your NMC paperwork in hand, not casually because Q300 looks smaller.
Q345 and Q346: Modules That Belong to Other Routes
Two additional Q-numbers appear in the NMC's published material for this scope, and they cause frequent confusion:
| Module | What it is | Is it part of a full original Master exam? |
|---|---|---|
| Q345 | Navigation and Deck General/Safety, a separate raise-of-grade module for Master less than 100 GRT to Master/Mate less than 200 GRT | No. It belongs to the raise-of-grade route. |
| Q346 | A separate route for OUPV to Mate less than 200 GRT | No. It is not an extra Master-original module. |
Separate upgrade, raise-of-grade, and route-extension modules are not additional domains stacked onto the full-original structure. They are alternative pathways for mariners who already hold a lower credential. If you are an original applicant, you prepare for the five groups above; if you are upgrading, your approval will reflect that.
Why Your Approval to Test Is the Final Word
The number of preparation groups is not a universal count of examinations for every applicant. The NMC determines each individual's assigned modules, and the authoritative record of what you must sit is your approval to test. Treat it as the source of truth over any article, including this one.
The same caution applies to numbers. The material this article is built on does not establish current fees, a population pass rate, a single overall question count, or percentage weightings. For anything involving money or scoring, look at current NMC guidance and see our companion pieces on NM2GI certification cost, pass rate data, and the passing score for what can and cannot be stated with confidence.
One more sourcing note for the careful reader: the published examination guide referenced here (section 2.1.2.3, printed page 27) reflects regulations effective March 24, 2014. It is not a newly issued 2026 blueprint. Current indexed NMC matrices corroborate the same module headings, which is why the structure above is stated with confidence, but it is worth knowing which document is the older one.
Where the Credential Gets Used
A Master or Mate endorsement for vessels under 200 GRT on Great Lakes and inland waters fits operations where vessels fall under that tonnage threshold and run on those waters. Think passenger and excursion vessels, towing and workboat operations, and other commercial deck work where a licensed officer is required. Employers in these segments typically care about the endorsement scope on your credential, so understanding exactly what GLI05 authorizes is part of being employable, not just exam-ready.
For a closer look at the employment side, see NM2GI jobs, and for earnings context see the NM2GI salary guide. Whether the investment pays off for you is a separate question handled in Is the NM2GI Certification Worth It? Complete ROI Analysis 2026.
Sequencing Your Preparation
General study technique is not the point of this article, but module structure does suggest a sensible order. Rules knowledge and chart work reinforce Navigation General, so it helps to build from the rules outward:
Rules of the Road (Q100, or Q300 if applicable)
- Rules vocabulary feeds nearly every later scenario
- Confirm your Q100 vs. Q300 route before investing time
Deck General (Q340) and Deck Safety (Q341)
- Concept-heavy groups that reward steady reading and review
Navigation General (Q342) and Chart Plot (Q343)
- Start chart plotting early and keep practicing; it is a skill, not a fact set
- Use Q342 theory to inform your Q343 problem-solving
For a full planning framework, the NM2GI Study Guide 2026 lays out a complete approach, and the NM2GI cheat sheet is useful for last-pass review. When you are ready to test yourself against realistic question styles, the main practice test site lets you drill each group separately.
Key Takeaway
Start by pulling your NMC approval to test and writing down your exact assigned modules. Then build your plan around those Q-numbers, not around a generic "five exams" assumption. Practice chart plotting early, and use targeted practice to find weak spots in each group.
Frequently Asked Questions
NM2GI stands for National Master 200 GL and Inland. It refers to the Master or Mate less than 200 GRT credential pathway for Great Lakes and inland waters, examined under NMC scope GLI05.
The United States Coast Guard National Maritime Center governs the credential. It determines your assigned examination modules and issues your approval to test.
No. Q100 and Q300 are alternatives. Great Lakes and Inland uses Q100, while Inland may use Q300 when the applicable COLREGS limitation is accepted. They are never counted together as simultaneous requirements.
In the full-exam structure, Chart Plot Q343 is required and must not be left out of your preparation. Confirm against your approval to test if you hold an upgrade or route-extension application.
No. Q345 is a separate raise-of-grade module for moving from Master less than 100 GRT to Master/Mate less than 200 GRT, and Q346 is a separate route for OUPV to Mate less than 200 GRT. Neither is an extra module for a full original Master application.
For the eligibility side of the process, continue with NM2GI requirements and how to qualify, and check NM2GI exam dates for scheduling considerations.