- What NM1N Means Here
- Who Stands Behind the Credential
- The Five-Module Structure Behind the Name
- Q100: Rules of the Road in Practice
- Q160: Deck General Topics
- Q161: Deck Safety and Stability
- Q162 and Q163: Navigation Knowledge and Chart Plotting
- Why Your Route Changes the Meaning
- Sequencing the Modules in Your Preparation
- Where the Credential Leads
- Frequently Asked Questions
- NM1N here means National Master 100 NC: Master Near Coastal, vessels under 100 gross register tons.
- The United States Coast Guard National Maritime Center governs the credential and publishes its exam modules.
- The original full exam draws on five modules: Q100, Q160, Q161, Q162 and Q163.
- Q165 belongs to a separate OUPV-to-Master raise-of-grade route, not the original five.
What NM1N Means Here
On this site, NM1N is shorthand for National Master 100 NC. Break the name apart and it tells you almost everything about the credential. "National" signals a U.S. federal mariner endorsement rather than a state or private certificate. "Master" is the top deck-officer authority on a vessel. "100" refers to the 100 gross register ton limit on the vessels covered. "NC" stands for Near Coastal, the geographic route category that extends beyond rivers and protected waters.
Put together, the credential covers a master's authority on near coastal vessels of less than 100 GRT. That is the working world of many charter boats, small passenger vessels, towboats, workboats and commercial fishing support craft operating off the U.S. coast. If you have seen the acronym attached to other credentials elsewhere, set those aside. This article, and the rest of the NM1N Exam Prep site, deals only with the Coast Guard Master Near Coastal under-100-GRT endorsement.
If you want the plain-language introduction first, our companion pieces What Is NM1N? and What Does NM1N Stand For? cover the same ground from slightly different angles. This article goes further by showing how the name maps onto the actual exam content.
Who Stands Behind the Credential
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 catalogs that define what a Master Near Coastal under-100-GRT candidate is expected to know.
Two practical points follow from that:
- The NMC defines the content. Study material should trace back to the NMC's published module topics, not to a vendor's invented outline.
- Approval to test is individual. The NMC's published guidance ties testing to your own approved application. The reference guide we rely on is the NMC Examination Guide with regulations effective 2024-03-24 era dating noted as 2014-03-24, and it should be read alongside the current published module-topic index rather than treated as a brand-new universal exam specification.
The Five-Module Structure Behind the Name
The original Master Near Coastal less-than-100-GRT full exam uses five NMC modules. Each carries a Q-code, and those codes are the vocabulary you will see in the Coast Guard's published exam pages.
| Domain | NMC Module | Core Subject Area |
|---|---|---|
| 1 | Q100 | Rules of the Road: International and Inland |
| 2 | Q160 | Deck General |
| 3 | Q161 | Deck Safety |
| 4 | Q162 | Navigation General: Near Coastal |
| 5 | Q163 | Navigation Problems: Chart Plot |
Older Coast Guard material for larger vessels used a split structure, with separate Deck General Part I and Part II headings and a standalone Stability Problems heading. That pattern belongs to a different, larger-vessel module arrangement and is not the NM1N domain structure. For NM1N, stability material lives inside Q161, which is why the Deck Safety module is more substantial than its name suggests.
For a deeper domain-by-domain walkthrough, see NM1N Exam Domains 2026: Complete Guide to All 5 Content Areas.
Q100: Rules of the Road in Practice
Domain 1: Rules of the Road: International and Inland (Q100)
The published topic headings for Q100 are Watchkeeping, COLREGS and the Inland Navigational Rules. The module tests whether you can apply both rule sets, because a near coastal master crosses the demarcation between inland and international waters.
- Know which set of rules governs the waters you are in and where the boundary falls.
- Be fluent in the right-of-way logic for crossing, meeting and overtaking situations.
- Understand lights, shapes and sound signals well enough to identify a vessel's status from a description.
- Treat watchkeeping as a rules topic: lookout, safe speed and risk of collision all appear in the catalog.
Q100 also has a role outside the full exam. For an increase in scope from Great Lakes or Inland to Near Coastal, the published guidance pairs Q160 and Q162, and adds Q100 where a COLREGS limitation applies. In other words, Q100 is the module that proves you understand the international rules, and it shows up precisely when that knowledge is the missing piece.
Q160: Deck General Topics
Deck General is the broadest module in the set, and its published topic list reads like a tour of everyday seamanship and vessel operations. Rather than one deep subject, Q160 asks you to be competent across many.
Domain 2: Deck General (Q160)
The catalog groups topics that candidates tend to underestimate because they feel familiar from working on the water.
- Seamanship and marlinspike: knots, splices, line handling, purchases, blocks and tackle.
- Vessel maneuvering and handling: turn circle, pivot point, advance and transfer, and wake reduction.
- Emergencies: collision, temporary repairs, abandon ship procedures, rescuing survivors from a ship or aircraft in distress, and passenger and crew safety.
- Fire: classes and chemistry of fire, fire prevention and firefighting appliances, and basic firefighting.
- Lifesaving: lifesaving appliance operation, survival at sea and signals including storm, wreck, distress and special signals.
- Administration and equipment: ship's business, certificates and documents required, communications and radiotelephone, vessel power plants and small engine operations and maintenance.
Notice how much of this is recall of specific procedures and definitions rather than judgment calls. Maneuvering terms such as pivot point, advance and transfer are the kind of precise vocabulary that separates a candidate who has handled boats from one who has studied the terms.
Q161: Deck Safety and Stability
Q161 is where the Master Near Coastal exam gets technical about the vessel itself. Its published headings include Stability, Construction and Damage Control, Principles of Vessel Construction, and Trim and Stability, alongside a block of emergency topics.
Domain 3: Deck Safety (Q161)
This module combines vessel-integrity knowledge with emergency response, and it is where the real stability material lives for NM1N.
- Stability and trim: how weight, free surface and flooding affect a small vessel's behavior.
- Construction and damage control: hull structure principles and how to limit flooding after damage.
- Emergency response: man overboard procedures, emergency towing, abandon ship procedures, and rescuing survivors.
- Fire and machinery: fire or explosion, fire prevention and firefighting appliances, vessel power plants and small engine operations and maintenance.
Q162 and Q163: Navigation Knowledge and Chart Plotting
The last two domains are both navigation, but they test different skills. Q162 is a knowledge module, and Q163 is a plotting module.
Q162: Navigation General: Near Coastal
Q162 covers the theory and reference side of getting a vessel from place to place. The catalog includes position determination, piloting, distance off, bearing problems, fix or running fix, dead reckoning, instruments and accessories, aids to navigation, and charts, navigation publications and Notices to Mariners. It also adds compass material (magnetic and gyro, compass error and correction, determination of compass error) and a meteorology and oceanography block covering weather systems, ocean currents, weather charts and reports, and tides and tidal currents.
Q163: Navigation Problems: Chart Plot
Q163 puts those concepts to work on a chart. Its catalog overlaps Q162 on piloting, distance off, bearing problems, fix or running fix, chart navigation and dead reckoning, and it adds electronic navigation. The distinguishing feature is that you are producing answers from a plot, not recalling definitions.
Key Takeaway
Treat Q162 and Q163 as a pair. Learn a concept such as a running fix in Q162 terms first, then immediately practice it on a chart in Q163 terms. Candidates who study them separately often discover that knowing the definition does not guarantee a clean plot.
Why Your Route Changes the Meaning
Because the NMC publishes different modules for different pathways, "NM1N" does not always mean the same exam package for every person. The published pages separate two groups:
| Pathway | Published Module Group | Note |
|---|---|---|
| Original Master Near Coastal less than 100 GRT, full exam | Q100, Q160, Q161, Q162, Q163 | The five domains used on this site |
| OUPV-to-Master Near Coastal less than 100 raise of grade | Q165 Navigation and Deck General/Safety | Separate module; not added to the original five |
| Increase in scope, Great Lakes or Inland to Near Coastal | Q160 plus Q162, plus Q100 where a COLREGS limitation applies | Published guide pathway |
Do not add these pathways together. A candidate on the increase-in-scope route does not owe the full five-module package on top of it, and a raise-of-grade candidate is not required to test the original five in addition to Q165. Confirm your own route and approval with the NMC before you build a study plan, and see NM1N Requirements 2026: Eligibility, Prerequisites & How to Qualify for the eligibility side.
Likewise, the NMC does not publish official percentage weights in the sources used here. The five domains on this site are unweighted, route-aware preparation groups, not a scored blueprint. That is why, for questions about scoring thresholds, our page on the NM1N passing score points you back to current NMC guidance instead of quoting a number.
Sequencing the Modules in Your Preparation
Since there is no published weighting to tell you where to spend time, sequence by dependency. Here is one NM1N-specific way to order the work for a full five-module candidate:
Q100 and the vocabulary of Q160
- Lock in COLREGS and Inland rules first; they are memorization-heavy and reward early repetition.
- Start Q160 seamanship, maneuvering terms and signals alongside it.
Q161 stability, construction and emergencies
- Work stability and trim as concepts before attempting any problem-style questions.
- Cover man overboard, emergency towing and abandon ship while Q160 overlap is fresh.
Q162 theory, then Q163 plotting
- Study compass error, tides and weather in Q162 before you plot.
- Finish with repeated chart plots covering fixes, running fixes and dead reckoning.
The logic is that navigation plotting is the most skill-dependent domain, so it benefits from the longest tail of practice. For fuller study methodology, our NM1N Study Guide 2026: How to Pass on Your First Attempt goes deeper, and the NM1N Cheat Sheet 2026 condenses the must-know facts into a single page for final review.
Where the Credential Leads
Holding a Master Near Coastal under-100-GRT endorsement positions you for command roles on smaller commercial vessels operating beyond protected waters. Typical employers include charter and passenger operators, tour and excursion boats, workboat and towing companies, and operators of other sub-100-GRT commercial vessels. The credential is a licensing step, and the specific job and pay you land depend on the employer, vessel and operating area.
We deliberately do not quote earnings figures here, since none are published in the NMC source material. If you are weighing the investment, our pieces on NM1N Jobs, whether the NM1N certification is worth it and the NM1N certification cost explore those questions qualitatively.
When you are ready to test your recall across all five domains, the NM1N practice test lets you drill the same module topics described above, and the main practice site is the best place to check which areas still need work before you apply to test.
Frequently Asked Questions
NM1N means National Master 100 NC, the U.S. Coast Guard Master Near Coastal endorsement for vessels of less than 100 gross register tons. The "NC" is Near Coastal, and "100" is the gross register ton limit.
The United States Coast Guard National Maritime Center governs the credential. It approves candidates to test and publishes the exam modules and topic catalogs that the study content is built from.
The original Master Near Coastal less-than-100-GRT full exam uses Q100, Q160, Q161, Q162 and Q163. These correspond to Rules of the Road, Deck General, Deck Safety, Navigation General: Near Coastal, and Navigation Problems: Chart Plot.
Not part of the original five. Q165 Navigation and Deck General/Safety is the separate module for the OUPV-to-Master Near Coastal under-100 raise of grade. Confirm your own route with the NMC before planning study.
The NMC sources used here do not publish percentage weights. The five domains are unweighted, route-aware preparation groups, so prepare all of them. For related details, see the NM1N meaning overview and our difficulty guide.