- What National Master 100 GL and Inland Actually Is
- Who Governs the Exam and What That Means
- The Five Preparation Groups
- The Route-Specific Rules Choice
- Where Q352 Fits (and Where It Does Not)
- Great-Lakes-Specific Topics
- Concrete Topics You Must Master
- Sequencing Your Preparation
- Who Uses This Credential
- Frequently Asked Questions
- NM1GI here means National Master 100 GL and Inland, issued through the U.S. Coast Guard National Maritime Center (NMC).
- Preparation breaks into five groups: Rules of the Road, Deck General, Deck Safety, Navigation General, and Chart Plot.
- The Rules group is Q100 or Q300, depending on the route approved for you.
- Q352 is a separate raise-of-grade module, not a sixth group for every original applicant.
What National Master 100 GL and Inland Actually Is
NM1GI is the shorthand used on this site for National Master 100 GL and Inland, a U.S. mariner credential for operating vessels of less than 100 gross register tons (GRT) on Great Lakes and inland waters. In the NMC's examination catalog the corresponding listing is GLI06, titled Master or Mate less than 100 GRT. This article keeps the Master identity throughout: the person studying for this credential is preparing for a deck officer role at the master level on smaller vessels.
Because the acronym is shared by several unrelated credentials elsewhere, it is worth stating plainly what this page covers. Everything below concerns the Coast Guard's licensing examination for masters of vessels under 100 GRT on Great Lakes and inland routes, and nothing else. If you want a shorter orientation to the name itself, our pages on what the NM1GI name means and what NM1GI stands for cover that angle.
Who Governs the Exam and What That Means
The governing body is the United States Coast Guard National Maritime Center. That has practical consequences for how you prepare:
- There is no commercial testing vendor model to assume. The NMC evaluates your application and issues an approval to test. Your specific modules come from that approval.
- The published reference is a regulatory guide. The NMC Examination Guide for deck and engineering exams reflects regulations effective 2014-03-24. Treat it as a topic reference, used alongside the NMC's current module-topic index and your individual approval, rather than as a new universal 2026 exam specification.
- Official percentage weights are not published here. Anyone quoting precise domain percentages for this credential is guessing. We present the content as unweighted, route-aware preparation groups.
The Five Preparation Groups
For a full-route original preparation, think in terms of five groups. These are not one common mandatory examination with fixed weights; they are the module families that your route-aware approval maps onto.
| Group | Module | Core flavor |
|---|---|---|
| 1 | Rules of the Road: International and Inland (Q100) or Inland (Q300) | Watchkeeping, COLREGS, Inland Navigational Rules |
| 2 | Deck General (Q347) | Seamanship, maneuvering, maritime law, shipboard management |
| 3 | Deck Safety (Q348) | Stability, firefighting, emergency procedures, signals |
| 4 | Navigation General: Great Lakes and Inland (Q349) | Piloting, compass, aids to navigation, weather, tides |
| 5 | Navigation Problems: Chart Plot (Q350) | Working chart problems: fixes, bearings, dead reckoning |
Note that the Rules choice counts once. You do not study both Q100 and Q300 as separate groups; your approved route determines which one applies. A deeper walk through each area lives in our complete guide to all five NM1GI content areas.
The Route-Specific Rules Choice
The first group is the one most likely to trip up candidates who skim their paperwork. The module is either Rules of the Road: International and Inland (Q100) or Inland (Q300), according to the route approved for you.
Domain 1: Rules of the Road
The published topics under this group are Watchkeeping, COLREGS, and the Inland Navigational Rules. Which rule set you must command depends on your approved route.
- Confirm on your approval whether you are assigned Q100 or Q300 before buying any study material.
- If you are on the International and Inland module, expect to keep both rule sets straight, including where they differ.
- If you are on the Inland module, concentrate on the Inland Navigational Rules and the watchkeeping principles that sit beside them.
Rules questions reward precision about who is the give-way vessel, what sound and light signals mean, and how watchkeeping duties are framed. Memorizing without understanding the situations behind the rules is the common failure pattern. Our look at how hard the NM1GI exam really is discusses why this module catches people who are otherwise strong mariners.
Where Q352 Fits (and Where It Does Not)
Q352, Navigation and Deck General/Safety, is listed separately by the NMC as a raise-of-grade route module. It exists for mariners moving up from an existing credential. It should not be read as:
- a universal sixth exam group appended to every full-original preparation, or
- a second Rules subject (it is not related to Q100 or Q300).
If you are an original applicant working through the five groups above, Q352 is not an extra hurdle you stack on top. If you are raising grade, your approval to test will tell you whether Q352 applies in place of some of the individual modules. This distinction is a frequent source of confusion on forums, so check your own approval rather than a peer's experience.
Great-Lakes-Specific Topics
Great-Lakes-and-Inland versus Inland-only applicability matters. In the NMC's topic table, certain items carry a footnote 3 marking them as Great-Lakes-specific:
- Heavy Weather Operations
- Maneuvering for Launching of Lifeboats and Liferafts in Heavy Weather
Both sit within Deck General (Q347). If your route is Great Lakes and Inland, treat these as live exam content. If your approved route is Inland only, the footnote tells you these topics are not expected of you in the same way. Again, your approval is the final word.
Key Takeaway
Before you study heavy-weather topics, check whether your approved route actually includes Great Lakes operation. Spending a week on lifeboat launching in heavy weather makes sense only if the footnote applies to you.
Concrete Topics You Must Master
The NMC's published catalog is specific enough to build a real study outline. Here is how it breaks down by module.
Deck General (Q347)
Domain 2: Deck General
This is the broadest seamanship module, covering both hands-on skills and the legal and managerial side of running a vessel.
- Seamanship and marlinspike: knots, splices, purchases, blocks, and tackle.
- Vessel maneuvering and handling: rivers and estuaries, shallow water, interaction with a bank or passing ship, berthing and unberthing.
- Anchoring and mooring: including dragging anchors and clearing fouled anchors.
- General handling concepts: turn circle, pivot point, advance and transfer, and wake reduction.
- Law and management: maritime law, national maritime law, credentialing of seamen, ship sanitation, vessel alteration, repair and hot work, safety, ship's business, and required certificates and documents.
Deck Safety (Q348)
Domain 3: Deck Safety
Expect scenario-driven questions about keeping the vessel and everyone aboard safe when things go wrong.
- Stability, construction, and damage control: principles of vessel construction, trim and stability.
- Fire: prevention, appliances, organizing fire drills, classes and chemistry of fire, firefighting systems.
- Emergency procedures: collision, temporary repairs, passenger and crew safety, fire or explosion, abandon ship, rescuing survivors from a ship or aircraft in distress, man overboard, emergency towing.
- Vessel power plants: small engine operations and maintenance.
- Communications: storm, wreck, distress, and special signals.
Navigation General: Great Lakes and Inland (Q349)
Domain 4: Navigation General
This module tests the knowledge behind the chart work: instruments, publications, compasses, and environmental factors.
- Position determination: piloting, distance off, bearing problems, fix or running fix, dead reckoning.
- Navigation tools: electronic navigation, instruments and accessories, aids to navigation, charts, navigation publications, and Notices to Mariners.
- Compasses: magnetic and gyro principles, compass error and correction, determining compass error by terrestrial observation.
- Environment: meteorology and oceanography, weather systems, weather charts and reports, tides and tidal currents.
Navigation Problems: Chart Plot (Q350)
Domain 5: Chart Plot
This is where theory becomes plotted answers. The listed topics overlap with Q349 by design, because here you apply them on a chart.
- Piloting, distance off, and bearing problems.
- Fix or running fix, chart navigation, and dead reckoning.
- Electronic navigation, instruments and accessories, aids to navigation.
- Charts, navigation publications, and Notices to Mariners.
Candidates who read about running fixes but never plot one tend to struggle with Q350. For a compact reference of facts worth memorizing, our NM1GI cheat sheet distills the highest-yield items.
Sequencing Your Preparation
Rather than a generic weekly template, sequence by dependency. Q349 knowledge feeds Q350 plotting, and the seamanship topics in Q347 overlap with emergency handling in Q348. A route-aware order might look like this:
Rules of the Road (Q100 or Q300)
- Confirm your assigned rule set first.
- Learn the rules through situations, then drill signals and lights.
Navigation General (Q349)
- Build compass, chart, publication, and tide fundamentals.
- This is the theory your plotting will depend on.
Chart Plot (Q350)
- Plot fixes, running fixes, and dead reckoning problems by hand.
- Practice until the procedure is automatic.
Deck General and Deck Safety (Q347, Q348)
- Cover maneuvering, anchoring, law, stability, fire, and emergencies.
- Add heavy-weather topics only if your route includes them.
Adjust the timing to your sea-service background. A working captain may compress seamanship and expand law and chart plotting. For fuller planning advice, see our NM1GI study guide, and test yourself against realistic questions on the main practice test site.
Who Uses This Credential
A master credential for vessels under 100 GRT on Great Lakes and inland waters is a working license for operators of smaller commercial vessels. Typical employers are the kinds of operators that run modest-tonnage vessels on lakes, rivers, bays, and sounds, such as passenger and charter operators, towing and workboat companies, and other small-vessel commercial fleets. Because licensing rules and employer expectations vary, confirm the requirements of any specific job before assuming this credential alone qualifies you.
For the career side, read our breakdowns of NM1GI jobs and the return on investment analysis. We deliberately avoid quoting salary or fee figures here, since we do not publish numbers we cannot source from the NMC; check the NMC's own fee information and our certification cost overview for how costs are structured.
Frequently Asked Questions
It stands for National Master 100 GL and Inland, the Coast Guard credential for masters of vessels under 100 GRT on Great Lakes and inland routes, listed by the NMC as GLI06.
The United States Coast Guard National Maritime Center. Your individual approval to test determines which modules, route, and any credit apply to you.
No. The Rules of the Road group is Q100 (International and Inland) or Q300 (Inland), according to your approved route. It counts as a single preparation group.
No. Q352 Navigation and Deck General/Safety is a separately listed raise-of-grade module. It is not a universal addition to the five full-original groups and is not a second Rules subject.
Official percentage weights are not published for this material, so treat the five groups as unweighted preparation areas. For scoring details, see our page on the NM1GI passing score, and for realistic outcomes see the pass rate discussion.