- What National Master 100 NC (NM1N) Actually Is
- Who Governs It and What That Means
- The Five Exam Modules Behind NM1N
- Why There Is No Single "NM1N Exam"
- Concrete Topics Candidates Must Master
- The Chart Plot Module in Detail
- Who Pursues This Credential and Who Hires
- Registration, Approval, and Fee Mechanics
- Sequencing Your Preparation Around the Modules
- Frequently Asked Questions
- NM1N here means National Master 100 NC: a Coast Guard credential for operating vessels under 100 GRT on near coastal waters.
- The original full exam draws on five modules: Q100, Q160, Q161, Q162, and Q163.
- Q165 is a separate OUPV-to-Master raise-of-grade module and is not part of the original five.
- Increase-in-scope routes from Great Lakes or Inland can use Q160 plus Q162, with Q100 added when a COLREGS limitation applies.
What National Master 100 NC (NM1N) Actually Is
National Master 100 NC (NM1N) is a United States Coast Guard mariner credential. It authorizes its holder to serve as master of vessels of less than 100 gross register tons (GRT) operating on near coastal waters. If you picture a captain running a charter fishing boat, a small passenger vessel, a dive boat, a tour operator, or a workboat beyond the inland boundary line, this is the type of license that puts a person legally in that seat.
The "NC" stands for Near Coastal, and the "100" refers to the tonnage ceiling of 100 GRT. In plain terms, the credential sits above the entry-level operator licenses and below the larger-tonnage master endorsements that cover bigger ships. It is a professional deck license, and earning it means proving competence in rules, seamanship, vessel safety, and navigation through Coast Guard examination modules.
This article focuses strictly on that credential and the way the exam content is organized. If you want a quick overview of related naming questions, our pages on what NM1N is and what NM1N stands for cover the shorthand, while this guide goes deeper on the structure of the exam itself.
Who Governs It and What That Means
The governing body is the United States Coast Guard National Maritime Center (NMC). The NMC publishes examination guides, maintains module topic indexes, evaluates applications, and issues approval to test. This matters for how you prepare, because the NMC is the source of record for what the exam covers.
The examination guide this article draws on reflects regulations effective 2014-03-24. That document should be used alongside the current published NMC module-topic index and your individual approval to test. It is not a brand-new 2026 universal exam specification, and you should not treat it as one. The NMC does not publish official percentage weights for these modules in the sources used here, so any claim you see online about exact percentage splits deserves skepticism.
The Five Exam Modules Behind NM1N
The original full exam for Master Near Coastal less than 100 GRT is built from five Coast Guard modules. The coding system uses a Q-number for each module, and the five that make up the original full exam are Q100, Q160, Q161, Q162, and Q163. On this site those five are treated as the five preparation domains.
| Domain | Module Code | Core Focus |
|---|---|---|
| Rules of the Road: International and Inland | Q100 | Watchkeeping, COLREGS, Inland Navigational Rules |
| Deck General | Q160 | Seamanship, maneuvering, emergencies, communications, firefighting, lifesaving |
| Deck Safety | Q161 | Stability, construction, damage control, man overboard, emergency towing |
| Navigation General: Near Coastal | Q162 | Piloting, compass, aids to navigation, meteorology, tides |
| Navigation Problems: Chart Plot | Q163 | Chart plotting, fixes, dead reckoning, electronic navigation |
For a domain-by-domain breakdown of how these areas fit together, see our complete guide to all 5 NM1N content areas.
Why There Is No Single "NM1N Exam"
Here is the point that trips up many first-time researchers: the Coast Guard does not administer one universal, fixed NM1N test that every candidate takes in the same form. The modules you actually sit depend on your route to the credential and what the NMC approves for you individually.
The groupings used on this site are best understood as unweighted, route-aware preparation groups rather than one common mandatory examination. Consider the pathways described in the published guidance:
- Original full exam: Q100, Q160, Q161, Q162, and Q163.
- Increase in scope from Great Lakes or Inland to Near Coastal: the published guide points to Q160 plus Q162, with Q100 added where a COLREGS limitation applies.
- OUPV-to-Master Near Coastal under 100 raise of grade: uses a separate module, Q165 (Navigation and Deck General/Safety), which is not part of the original five.
Do not add these pathways together. A candidate on an increase-in-scope route does not suddenly owe all five modules plus Q165. Likewise, the old split Deck General Part I and Part II headings, and separate Stability Problems headings, belong to a different larger-vessel module pattern and are not the structure for this credential. Stability topics for NM1N live inside Q161.
Concrete Topics Candidates Must Master
Knowing the module names is only the start. Each module has a published topic catalog, and these are the areas where candidates spend their study time.
Domain 1: Rules of the Road: International and Inland (Q100)
This module covers the rules that govern how vessels avoid collisions and conduct themselves underway.
- Watchkeeping responsibilities
- COLREGS (International Rules)
- Inland Navigational Rules
Domain 2: Deck General (Q160)
The broadest module by topic count. It blends practical seamanship with emergency response and vessel operations.
- Seamanship, marlinspike seamanship, and purchases, blocks, and tackle
- Vessel maneuvering and handling, including turn circle, pivot point, advance and transfer, and wake reduction
- Collision response and temporary repairs
- Fire or explosion, classes and chemistry of fire, and firefighting appliances
- Abandon ship procedures, lifesaving, lifesaving appliance operation, and survival at sea
- Rescuing survivors from a ship or aircraft in distress
- Communications and communications radiotelephone
- Signals: storm, wreck, distress, and special
- Ship's business and certificates and documents required
- Vessel power plants and small engine operations and maintenance
Domain 3: Deck Safety (Q161)
Focused on keeping the vessel afloat and the people aboard alive when things go wrong.
- Stability, construction, and damage control
- Trim and stability
- Principles of vessel construction
- Man overboard procedures
- Emergency towing
- Passenger and crew safety in emergencies
- Fire prevention and firefighting appliances, plus abandon ship and rescue topics that overlap with Deck General
Domain 4: Navigation General: Near Coastal (Q162)
The theory side of navigation, including the instruments and environmental knowledge a near coastal master relies on.
- Piloting, distance off, bearing problems, and fix or running fix
- Dead reckoning and chart navigation
- Aids to navigation and charts, navigation publications, and Notices to Mariners
- Magnetic and gyro compass, compass error, correction, and determination of error
- Terrestrial observation
- Meteorology and oceanography: weather systems, ocean current systems, weather charts and reports
- Tides and tidal currents
Notice the overlap. Several topics, including fire, abandon ship, rescue, and power plants, appear in both Q160 and Q161. That repetition is useful: studying them once thoroughly pays off across two modules.
The Chart Plot Module in Detail
Q163, Navigation Problems: Chart Plot, is where theory becomes applied work. Candidates work navigation problems on a chart, covering piloting, distance off, bearing problems, fixes and running fixes, chart navigation, dead reckoning, and electronic navigation, along with instruments and accessories, aids to navigation, and charts, publications, and Notices to Mariners.
This is the module where practice with plotting tools matters most. Reading about a running fix is not the same as plotting one accurately and quickly. If you plan to pace yourself across the domains, treat chart plotting as a skill you build with repetition on actual charts, not something you can absorb by reading alone.
Key Takeaway
Q162 and Q163 share many topic names, but they test them differently. Q162 asks what you know about navigation concepts and tools. Q163 asks you to work problems on a chart. Prepare for both formats, not just one.
Who Pursues This Credential and Who Hires
The master near coastal credential for vessels under 100 GRT is the working license for a wide range of small commercial vessel operations. Typical employers and settings include:
- Charter fishing and six-pack style charter operations venturing beyond sheltered waters
- Small passenger vessel operators, including tour, sightseeing, and ferry services
- Dive boat and eco-tour operators
- Towing and assist companies running small tugs and workboats
- Offshore support and crew boat operators running smaller hulls
- Marine construction, survey, and utility companies that operate their own vessels
- Pilot boat and harbor service operators
Mariners often arrive at this credential after building sea service on an operator license, then seeking the master endorsement to take command or to expand the waters they may operate on. For a look at career outcomes, our pages on NM1N jobs and the NM1N salary guide cover the employment side, and is the NM1N certification worth it weighs the investment.
Registration, Approval, and Fee Mechanics
Unlike many commercial certification exams that you simply schedule online with a vendor, this credential runs through the Coast Guard's mariner credentialing process. The key mechanic is individual approval to test. The National Maritime Center reviews your application and, when you qualify, approves you to take the specific modules associated with your route. Your approval governs what you sit, which is why the route-aware framing above matters in practice.
On fees and timing, this guide deliberately avoids quoting universal figures. Fees, timers, and testing logistics are not presented here as fixed universal numbers, and combining numbers from different pathways would be misleading. For current charges and scheduling, rely on the NMC and your approval paperwork. If you want a broader view of the investment, see the NM1N certification cost breakdown and the NM1N exam dates guide.
Similarly, passing thresholds are set by the Coast Guard for each module. Our NM1N passing score article addresses how scoring works, and candidates curious about outcomes can consult the NM1N pass rate discussion for what can and cannot be said from available information.
Sequencing Your Preparation Around the Modules
Rather than a generic study calendar, it helps to order the modules by how they build on each other and by how much hands-on skill each requires. Here is one reasonable sequence for a candidate facing the full original five modules.
Rules of the Road (Q100)
- Learn COLREGS and Inland Rules side by side, noting where they differ
- Rules knowledge supports nearly everything else, so lock it in early
Deck General (Q160)
- Cover seamanship, maneuvering, firefighting, lifesaving, and communications
- This is the widest topic list, so give it the most calendar time
Deck Safety (Q161)
- Concentrate on trim and stability, construction, damage control, and emergency towing
- Overlapping fire and abandon-ship topics should already feel familiar
Navigation General and Chart Plot (Q162, Q163)
- Study compass, weather, and tides, then move straight into plotting practice
- Spend the final stretch working real chart problems under time awareness
Why this order? Rules and deck knowledge are largely recall and comprehension, while chart plotting rewards repetition, so putting it last lets you keep drilling right up to test day. If your route lists fewer modules, simply drop the ones you are not approved to take. For a fuller method, our NM1N study guide expands on this, and the NM1N cheat sheet is useful for a final review.
How Hard Is It, and How to Practice
Difficulty is subjective and depends on your sea time, your comfort with chart work, and how recently you studied. Mariners who work on the water daily often find Deck General familiar but underestimate the rules and plotting modules. Candidates with strong academic backgrounds sometimes find the opposite. Our NM1N difficulty guide explores this in depth.
To test where you stand before approval day, work through realistic questions mapped to each module. The NM1N Exam Prep practice test site organizes practice by these five domains so you can identify weak spots early, and the main practice tests let you drill the topics that give you the most trouble, whether that is stability concepts or running fixes.
Frequently Asked Questions
On nm1nexam.com, NM1N refers to National Master 100 NC, the United States Coast Guard credential for master of vessels under 100 GRT on near coastal waters. It does not refer to any other credential that happens to share the acronym.
The original Master Near Coastal less than 100 GRT full exam uses Q100 (Rules of the Road), Q160 (Deck General), Q161 (Deck Safety), Q162 (Navigation General: Near Coastal), and Q163 (Navigation Problems: Chart Plot).
Not in the original five. Q165, Navigation and Deck General/Safety, is a separate module for the OUPV-to-Master Near Coastal under 100 raise-of-grade route. It should not be added on top of the original five modules.
No. The modules you sit depend on your pathway and your individual approval to test from the National Maritime Center. An increase in scope from Great Lakes or Inland, for example, uses Q160 and Q162, with Q100 added if a COLREGS limitation applies.
Stability, trim, construction, and damage control are part of Deck Safety (Q161). They are not a separate Stability Problems module for this credential, since that heading belongs to a different larger-vessel module pattern.
Understanding this credential starts with understanding its structure: a Coast Guard master license built from route-dependent modules rather than one fixed test. Confirm your pathway with the National Maritime Center, learn the topics in each module you are approved for, and use the broader NM1N certification overview and what is NM1N certification resources to fill in remaining gaps as you plan your path to the wheelhouse.