01
Answer a real question
An NMC-format question from the paper you will sit, in the format the NMC uses.
USCG OUPV & Master · exam prep
Pass your USCG captain’s exam on the rules, not on guesses.
OUPV (Six-Pack) and Master under 100 GRT. Real exam-style questions, and every answer traced to 33 & 46 CFR, the COLREGs or Bowditch, so you can check us instead of trusting us.
- 4,000+ judge-verified questions
- Every answer cited
- NMC-format timed mocks
Electrical measuring devices and instrumentation
When using an ohmmeter to measure the resistance of a motor winding, the technician must first ensure the motor is:
100%
of answers carry a source citation
4,000+
judge-verified questions
9
primary sources, dated and listed
How it works
Three moves, and the first one is free
You are already past step one if you answered the question above.
02
Read why, with the rule
The explanation opens with the regulation it tests and links to the text. Wrong answers teach more than right ones.
03
Get a plan to your exam date
Your misses become week one. The plan reorders itself every time you drill.
How we compare
Against the free bank you already use, and the course you are pricing
Two honest competitors. One is free and unexplained, the other is $600–900 and in a classroom.
Where the answer comes from
- CaptainsGround
- The rule, quoted and linked
Question format
- CaptainsGround
- NMC format, judge-verified
Plan from your exam date
- CaptainsGround
- Week by week, adapts
Spaced repetition
- CaptainsGround
- FSRS-4 scheduler
Free tier
- CaptainsGround
- 20 drills/day · 1 sample mock · plan outline
Cost
- CaptainsGround
- $79 one-time, 90 days
Where to start
Pick the credential you are going for
If you cannot name it yet, that is the most common answer. Start there.
Most common
OUPV — the Six-PackUp to six passengers on an uninspected vessel. Near coastal, or Great Lakes and inland.
What it takesUpgrade
Master under 100 GRTInspected vessels and larger charters. Five modules, graded as one 210-question series at 70%.
What it takesEntry
Able Seaman & QMEDDeck and engine ratings. Different papers, same citation rule.
See the ratingsNot sure
I don’t know which one I needThree questions about the boat, the water and the passengers, and we will name it.
Find outWhat costs money
Free is not a trailer
Free, forever
$0
20 drill questions a day, one sample mock and a plan outline — free, no card.
When the cap gets in the way
$79 one-time · 90 days
Unlimited drills, every full-length mock, the full plan and readiness scoring. No auto-renew, 14-day refund.
FAQ
The questions people actually ask before starting
Is this affiliated with the USCG or NMC?
No. CaptainsGround is an independent study tool, not affiliated with, endorsed by or sponsored by the U.S. Coast Guard or the National Maritime Center. The corpus is built from public-domain federal sources — 33 and 46 CFR, the COLREGs, the Inland Rules, NGA Bowditch and USCG manuals.
What is free, and what costs money?
20 drill questions a day, one sample mock and a plan outline — free, no card. When the daily cap gets in the way, the Exam Prep Pass is $79 one-time, 90 days, no auto-renew. 14-day refund.
Will this prepare me for the actual NMC exam?
The mock exam mirrors the NMC format — 70 questions in 90 minutes, weighted by module. Rules of the Road and Chart Plotting are graded at 90% on the OUPV and Great Lakes papers, which means five misses of fifty still passes and the sixth ends the attempt; everything else is 70%.
What credentials do you cover?
OUPV Near Coastal, Great Lakes & Inland, and Master under 100 GRT, plus the Able Seaman and QMED ratings. Set yours during onboarding and the plan adapts.
How long does prep take?
Most candidates finish in 6–10 weeks at 8 hours a week. A two-week sprint works for experienced mariners willing to put in 15 hours a week.
Can I use this on my phone?
Yes. The site works on any screen, and there are native apps on both stores — free, same account, same free tier. The app adds two things a browser cannot do: a daily reminder at an hour you pick, and lessons you have already opened read with no connection. New lessons still need one.
What if I find a wrong answer?
Every drill question is judge-validated against the cited source before it publishes. Found a discrepancy? Email us — corrections re-run through the pipeline.
On your phone
The app exists for the two things a browser cannot do
Everything else is the same product — the same questions, the same citations, the same plan. Free on both stores.
A reminder at the hour you pick
Set it once — 19:00 by default — and the app nudges you at the same time each day. A fixed time is most of what makes a streak survive. A browser cannot do this.
Lessons you have opened read without a signal
Anything you have already read stays on the phone and opens instantly, which is the situation a mariner studying on a vessel is actually in. New lessons still need a connection.
The same account and the same free tier
Twenty drill questions a day, one full mock, the whole flashcard deck, and the citation on every answer. Sign in and your plan, streak and cards are already there.
Five questions is thirty seconds. Guessing is an exam fee.
No signup, no card. You will know your weakest module before you finish your coffee.