Nav Rules: COLREGS Exam Prep

USCG Rules of the Road practice tests, diagrams and the full rule text — offline.

Rules of the Road is the module that fails people. It is closed book, it is usually graded at 90%, and the International and Inland texts differ in ways that are easy to mix up under time pressure. Nav Rules is built for that one problem.

1,200 questions, 83 original diagrams, and the complete rule text in 52 chapters — all bundled inside the app. It works at sea, at the dock, and in the yard, because it never needs a signal.

No account. No ads. No subscription. No in-app purchases. One purchase and it is yours.

Study Material

• 1,200 multiple-choice questions covering International, Inland, and rules that apply to both.
• 83 original vector diagrams for lights, shapes, and vessel encounters — tap any one for full screen, pinch to zoom.
• The complete rule text in 52 chapters, with International and Inland shown side by side so you can see exactly where the two diverge.
• 54 further figures inside the rule text itself.
• Full-text search across every rule and every question.

Practice the Way You Study

• Filter by zone: International, Inland, or both.
• Filter by topic: lights and shapes, sound and light signals, steering and sailing, restricted visibility, general definitions, distress, annexes, inland-specific.
• Filter by where you stand: unseen, previously missed, bookmarked, or due for review today.
• Instant grading the moment you tap an answer.
• Links to the rule text: many questions link through to the sections that may be relevant, so you can read the actual wording instead of memorizing an answer.

Exam Mode

• Choose your question count and zone, start the timer, and get no feedback at all until you submit — the way the real thing works.
• Results scored against the 90% line, with your misses grouped by topic.
• Every question in the session is available for review afterward.
• Answer choices are reordered wherever the wording allows, so you can never fall back on remembering a position.

Remember It Until Test Day

• Spaced repetition schedules each question to return just before you would have forgotten it.
• Missed questions stay missed until you have answered them correctly and consistently.
• Bookmark anything you want to come back to.

Know Where You Stand

• A readiness dial estimates your score for each zone.
• A topic heatmap shows which areas are weak.
• Per-rule accuracy tells you which specific rule to go reread.
• Streaks, total questions answered, and average time per question, all tracked.

Built for How Mariners Study

• 100% offline. No signal needed, ever.
• No account, no sign-up.
• No ads, no subscription, no in-app purchases.
• Optional iCloud sync keeps your progress in step across iPhone and iPad — off by default, and it runs through your own iCloud account.
• Dark appearance by default, plus an extra font size step above the system setting for anyone who wants larger type.

Who It Is For

Candidates for OUPV (six-pack), Master under 100 tons, and Mate/Master at every level. Academy and maritime school students working through the rules alongside coursework. Boat owners who simply want to understand what the lights ahead of them mean.

Why You’ll Love It

Everything is in one place and none of it needs a connection: the questions, the diagrams, and the rule text they come from. The app tells you honestly which rules may be relevant to a question rather than pretending a keyword match is a citation — the rule text itself is the authority, and the app is worded that way throughout.

Nav Rules is an independent study aid. It is not affiliated with, endorsed by, or an official publication of the U.S. Coast Guard or the National Maritime Center.