Deck
USCG Master of Vessels Less Than 100 GRT
- Modules
- 5
- Lessons
- 15
- Questions
- 75
AI-drafted catalogue content pending SME review. USCG requirements change; verify every figure against the National Maritime Center and the current CFR before relying on it for an application.
Aligned to the published USCG framework. Official source. Drafted from 46 CFR Parts 10 & 11 (esp. 11.422, 11.428, 11.455, 11.457), 33 CFR Parts 62/80/83, and NMC checklist MCP-FM-NMC5-15 (08), 15 Sep 2025..
USCG-MASTER100-M1 · The credential
4 lessons
USCG-MASTER100-M1-A What Master under 100 GRT authorises, the tonnage formula, routes, sea service and the examination.
Practice in examiner ↗USCG-MASTER100-L1.1What Master under 100 GRT authorisesThe OUPV lets you carry six people for money on a boat nobody inspects. The Master under 100 GRT lets you command an **inspected** vessel carrying a great many more. That is the whole difference, and it is a large one.USCG-MASTER100-L1.2The tonnage formula: how 25, 50 and 100 are decidedThere is no such thing as a "Master 50 Ton licence" you apply for. There is one credential — Master of vessels less than 100 GRT — and a **formula** that decides what tonnage it is limited to. You do not choose the tier. Your logbook chooses it for you, years before you apply.USCG-MASTER100-L1.3Routes and sea serviceThree routes, and the service required for each differs sharply. The near-coastal route costs twice what the others do, and the reason is simply that it is worth twice as much.USCG-MASTER100-L1.4Eligibility, the application, and the examinationThe supporting requirements are broadly those of the OUPV, with a handful of differences that matter. What is genuinely different is the examination, which is longer and harder.
USCG-MASTER100-M2 · Raising and extending the ticket
3 lessons
USCG-MASTER100-M2-A Raising the tonnage limitation, and the sail and assistance towing endorsements.
Practice in examiner ↗USCG-MASTER100-L2.1Raising the tonnage limitationYou have been issued a Master limited to 25 or 50 GRT and you want 100. The regulation gives you four separate ways to get there, and they are not equally expensive.USCG-MASTER100-L2.2The sail and auxiliary sail endorsementA Master under 100 GRT is issued for **self-propelled** vessels. If you intend to command a sailing vessel commercially, you need the auxiliary sail endorsement — and the sail charter trade is a large part of why this credential exists at all.USCG-MASTER100-L2.3The assistance towing endorsementTowing a disabled vessel for money is a commercial act, and it needs an endorsement. It is also, in the small-craft world, one of the most reliable ways to be sued.
USCG-MASTER100-M3 · Deck General (exam module Q160)
3 lessons
USCG-MASTER100-M3-A Stability, vessel systems and the master's inspections, and weather. 50 questions at 70%.
Practice in examiner ↗USCG-MASTER100-L3.1Stability for the small vessel masterSmall passenger vessels do not usually sink because the sea beat them. They capsize because everyone went to one side to look at the whale. Stability is the part of this job where the arithmetic and the deaths are most directly connected.USCG-MASTER100-L3.2Vessel systems and the master's inspectionsNobody is coming to check your boat before you sail. On an inspected vessel the Coast Guard checks her once a year; on the other 364 days the master is the inspection. That is not a figure of speech — it is where the legal responsibility actually sits.USCG-MASTER100-L3.3WeatherYou will make the go/no-go call in front of paying passengers who have driven three hours and booked a hotel. That is the actual test, and no amount of meteorology helps if you cannot say no.
USCG-MASTER100-M4 · Deck Safety (exam module Q161)
3 lessons
USCG-MASTER100-M4-A Responsibility for passengers, emergency preparedness and drills, search and rescue. 50 questions at 70%.
Practice in examiner ↗USCG-MASTER100-L4.1The master's responsibility for passengersYour passengers do not know where the life jackets are. They do not know which way is forward. They will not hear you over the engine, and in an emergency roughly half of them will do nothing at all. Every safety system on the vessel has to work around those facts.USCG-MASTER100-L4.2Emergency preparedness and drillsAn emergency plan that exists only in the master's head is not a plan; it is an intention. The regulation requires it posted, and the reason is that on the day, you will be busy driving the boat.USCG-MASTER100-L4.3Search and rescue, and helping othersOne day the Mayday will be someone else's. What you do in the next few minutes is governed partly by law and mostly by whether you have thought about it before.
USCG-MASTER100-M5 · Navigation (exam modules Q162 and Q163)
2 lessons
USCG-MASTER100-M5-A Navigation general at 200 miles, electronic navigation and radar, and the chart plot. 50 questions at 70% plus 10 at 90%.
Practice in examiner ↗USCG-MASTER100-L5.1Navigation General at Master levelThe navigation examined here is the same navigation as the OUPV, asked harder and further offshore. What changes is that near coastal now means **200 miles**, and at 200 miles the shortcuts stop working.USCG-MASTER100-L5.2Chart plot at Master levelTen questions, one allowed wrong, and you have three and a half hours. There is no excuse for an arithmetic error in this module, and arithmetic errors are what people fail it on.