- What National Master 100 NC (NM1N) Actually Covers
- The Five Content Areas at a Glance
- Domain 1: Rules of the Road (Q100)
- Domain 2: Deck General (Q160)
- Domain 3: Deck Safety (Q161)
- Domain 4: Navigation General, Near Coastal (Q162)
- Domain 5: Navigation Problems, Chart Plot (Q163)
- Route-Aware Preparation: Not Every Candidate Tests All Five
- Sequencing the Domains in Your Study Plan
- Frequently Asked Questions
- NM1N is the USCG National Maritime Center's Master Near Coastal under 100 GRT credential, tested through modules Q100, Q160, Q161, Q162 and Q163.
- Official percentage weights for these five areas are not published, so treat them as unweighted preparation groups.
- Q162 and Q163 overlap heavily on piloting, fixes and dead reckoning, so practice them together.
- Q165 is a separate raise-of-grade module and is not one of the original five.
What National Master 100 NC (NM1N) Actually Covers
National Master 100 NC (NM1N) refers to the U.S. Coast Guard credential for Master of vessels under 100 gross register tons operating Near Coastal. The examinations are administered through the United States Coast Guard National Maritime Center (NMC). Unlike many professional certifications, there is no single commercial test vendor and no universal "exam day" experience; the NMC publishes module-based examination material, and your approval to test determines what you sit.
The original full examination for this credential draws on five NMC modules: Q100, Q160, Q161, Q162 and Q163. This guide walks through each one, using the NMC's published module and topic catalog. If you are brand new to the credential itself, start with What Is NM1N? and NM1N Requirements 2026: Eligibility, Prerequisites & How to Qualify, then come back here to map your preparation.
The Five Content Areas at a Glance
The five modules fall into three broad families: the rules that govern how vessels interact, the seamanship and safety knowledge a master needs, and the navigation skills used to find and fix a position. Official percentage weights are not published for these areas, so the table below describes subject matter, not scoring emphasis.
| Domain | Module | Core Subject Matter |
|---|---|---|
| 1. Rules of the Road: International and Inland | Q100 | Watchkeeping, COLREGS, Inland Navigational Rules |
| 2. Deck General | Q160 | Seamanship, maneuvering, lifesaving, firefighting, communications, ship's business |
| 3. Deck Safety | Q161 | Stability, vessel construction, damage control, emergency procedures |
| 4. Navigation General: Near Coastal | Q162 | Position determination, compasses, aids to navigation, meteorology, tides |
| 5. Navigation Problems: Chart Plot | Q163 | Chart plotting, piloting, fixes, dead reckoning, electronic navigation |
Domain 1: Rules of the Road: International and Inland (Q100)
Q100 covers the rules that keep vessels from colliding. The NMC catalog lists three topic headings: Watchkeeping, COLREGS (the International Regulations for Preventing Collisions at Sea) and the Inland Navigational Rules.
What to master in Q100
A master must know both rule sets and, critically, where they differ.
- Right-of-way relationships: give-way versus stand-on vessels in crossing, meeting and overtaking situations
- Lights, shapes and sound signals for vessels underway, at anchor and restricted in their ability to maneuver
- Lookout and watchkeeping responsibilities under the rules
- The boundary between COLREGS waters and Inland waters, and which rule set applies where
The most common trap is mixing the two rule sets. Inland maneuvering and whistle signals differ from their international counterparts, and an answer that is correct under one regime can be wrong under the other. Build a side-by-side comparison as you study rather than memorizing each set in isolation. The NM1N Cheat Sheet 2026 is a good place to consolidate those contrasts once you have worked through the material.
Domain 2: Deck General (Q160)
Q160 is the broadest module by topic count. The NMC catalog lists a long run of headings that together describe the practical knowledge of running a small commercial vessel. Rather than one deep subject, expect many moderately deep ones.
Seamanship and Vessel Handling
This cluster includes seamanship, marlinspike seamanship, purchases, blocks and tackle, temporary repairs, collision response, and vessel maneuvering and handling. The handling topics specifically name turn circle, pivot point, advance and transfer, and wake reduction. Know how a vessel behaves when you turn it, not just the definitions.
Emergency Response and Lifesaving
Expect topics such as passenger and crew safety in emergencies, abandon ship procedures, rescuing survivors from a ship or aircraft in distress, survival at sea, lifesaving appliance operation, and emergency procedures.
Fire
The catalog covers the classes and chemistry of fire, fire prevention and firefighting appliances, basic firefighting and prevention, and fire or explosion scenarios. Link the class of fire to the appropriate extinguishing agent and know why the wrong agent can make things worse.
Communications, Documents and Machinery
Also listed are communications and radiotelephone procedures, storm, wreck, distress and special signals, certificates and documents required, ship's business, vessel power plants, and small engine operations and maintenance.
Domain 3: Deck Safety (Q161)
Q161 concentrates on how a vessel is built, how it stays upright and afloat, and what to do when something goes wrong. The catalog's lead heading is Stability, Construction, and Damage Control, supported by Trim and Stability and Principles of Vessel Construction.
Stability and construction
This is the conceptual core of the module and the area where many deck officers need the most deliberate practice.
- Trim and stability fundamentals as they apply to a small vessel
- Principles of vessel construction and how structure relates to damage control
- Damage control priorities after flooding or hull damage
Q161 also repeats several emergency headings that overlap with Q160, including passenger and crew safety in emergencies, abandon ship procedures, fire or explosion, rescuing survivors, vessel power plants and small engine operations and maintenance. It adds Man Overboard Procedures and Emergency Towing, two operational topics worth drilling because they are scenario-driven and reward a clear step-by-step mental sequence.
Because Q160 and Q161 share emergency material, studying them together saves time. Learn the emergency content once, deeply, then layer the module-specific items (stability and construction for Q161; seamanship and communications for Q160) on top.
Domain 4: Navigation General: Near Coastal (Q162)
Q162 tests the theory behind navigation rather than the plotting itself. The catalog groups its topics under position determination, compasses, and the physical environment.
Position determination and piloting
Core headings include navigation and position determination, piloting, distance off, bearing problems, fix or running fix, chart navigation, dead reckoning, and instruments and accessories.
- Distance-off and bearing relationships
- Constructing a fix and a running fix
- Dead reckoning logic and its limitations
Aids, charts and publications
Aids to navigation, charts, navigation publications and Notices to Mariners all sit here. Knowing how a chart is kept current, and where to find the correction information, is as testable as reading a symbol.
Compasses
The compass cluster includes magnetic and gyro compasses, principles of the magnetic compass, magnetic compass error and correction, determination of compass error, and terrestrial observation. Be fluent converting between true, magnetic and compass readings and applying variation and deviation in the right direction.
Meteorology, oceanography and tides
Characteristics of weather systems, ocean current systems, weather charts and reports, and tides and tidal currents round out the module. These are knowledge items you can learn from reading, but tidal current questions often feed directly into navigation problems, so practice applying them rather than just recalling them.
Domain 5: Navigation Problems: Chart Plot (Q163)
Q163 is the hands-on counterpart to Q162. Its catalog headings overlap with Q162, including navigation and position determination, piloting, distance off, bearing problems, fix or running fix, chart navigation, dead reckoning, instruments and accessories, aids to navigation, and charts, navigation publications and Notices to Mariners. It additionally lists Electronic Navigation.
The difference is the format. Where Q162 asks you to demonstrate understanding, Q163 asks you to work a problem on a chart: plot a course, lay down bearings, resolve a fix, and carry a dead reckoning position forward. Accuracy, neatness and consistent technique matter, because a small plotting error early in a problem carries through every later answer.
Key Takeaway
Treat Q162 and Q163 as one subject taught two ways. Learn the concept in Q162 terms, then immediately reinforce it by plotting a problem. Concepts you only read about tend to fall apart under chart-plot conditions.
For a realistic sense of where candidates struggle, see How Hard Is the NM1N Exam?. Most of the difficulty tends to concentrate in the chart-work and stability material rather than the memorization-heavy modules.
Route-Aware Preparation: Not Every Candidate Tests All Five
It is a mistake to assume every NM1N candidate sits the same five modules. The five-module set above describes the original Master Near Coastal under 100 GRT full examination. Other pathways draw on different combinations.
| Pathway | Modules Referenced |
|---|---|
| Original Master Near Coastal under 100 GRT full exam | Q100, Q160, Q161, Q162, Q163 |
| Increase in scope (Great Lakes or Inland to Near Coastal), published guide | Q160 and Q162, plus Q100 where a COLREGS limitation applies |
| OUPV-to-Master Near Coastal under 100 raise of grade | Q165, Navigation and Deck General/Safety (a separate module) |
Practical consequence: before you invest weeks in a domain, confirm it is on your approval. A candidate upgrading scope may skip entire modules that a full-exam candidate must master. For the eligibility side of this, revisit NM1N Requirements 2026, and for scheduling logistics see NM1N Exam Dates 2026. Fees and timing vary by situation and are not uniform, so rely on the official NMC pages and the NM1N Certification Cost 2026 breakdown for the cost picture rather than assuming a single universal figure.
Sequencing the Domains in Your Study Plan
Generic study habits matter less than the order in which you take on these five modules. Because several topics recur across modules, a deliberate sequence avoids relearning the same material. This is one possible arrangement for a full five-module candidate.
Q100 Rules of the Road
- Build COLREGS versus Inland comparison sheets
- Drill lights, shapes and sound signals until automatic
Q160 and Q161 together
- Learn the shared emergency material once
- Then add seamanship, communications and documents (Q160) and stability, construction and damage control (Q161)
Q162 and Q163 together
- Alternate concept study with chart-plot practice
- Work compass error, fixes, running fixes and dead reckoning repeatedly
Integrated review
- Revisit your weakest module
- Take timed practice sets across all five areas
The logic: rules come first because they are self-contained and build confidence; the two knowledge modules that share emergency content go together to avoid duplication; and navigation comes last with the most time because chart work is a skill that improves only with repetition. For a broader framework, see the NM1N Study Guide 2026, and for expectations on results, NM1N Passing Score 2026 and NM1N Pass Rate 2026.
When you are ready to test your recall under realistic conditions, the NM1N practice tests let you drill each domain separately, and the full practice question bank helps you find the gaps before the real examination does.
Frequently Asked Questions
The original Master Near Coastal under 100 GRT full examination uses five NMC modules: Q100, Q160, Q161, Q162 and Q163. Other pathways, such as increases in scope, draw on different combinations of these.
Official percentage weights are not published, so treat the five areas as unweighted preparation groups. Do not rely on any figure claiming a precise percentage split for each domain.
No. Q165, Navigation and Deck General/Safety, is a separate module used for the OUPV-to-Master Near Coastal under 100 raise of grade. It is not one of the original five and should not be added to them.
They share many topic headings, including piloting, fixes, bearing problems and dead reckoning. Q162 tests the underlying knowledge, while Q163 tests your ability to plot problems on a chart. Studying them together reinforces both.
Your NMC approval to test specifies your modules. Pathway matters, so confirm against your approval rather than assuming. See NM1N Requirements 2026 and the exam dates guide for related details.