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COLREG 72: safety at sea

by Smirnov Yury

  • Education
  • Paid
View on the App Store
Rating
4.7
214 ratings · UK storefront
Last update
Oct 19, 2026
Version 2.8.0
Size
76 MB
Category
Education
Tracked since
Oct 10, 2026

Estimated revenue

A model estimate with a likely range, not a reported figure.

No estimate. Apps outside the grossing charts, and some countries, have no reliable rank-to-revenue curve, so we show nothing rather than a guess.

How this estimate is made

Rank: we take the app's best Top Grossing rank on the latest chart day. Category ranks are converted into an equivalent overall rank, because a #10 in Finance earns far less than a #10 overall.

Curve: that equivalent rank is read off a rank-to-revenue curve anchored on public company revenue and market-data reports for the US iPhone App Store.

Country: the curve is scaled per country (Japan is roughly a third of the US, Türkiye under 1%). Where we have no scale, such as China, there is no estimate.

Range: the likely range widens with country, category and chart depth. It is a plausible span, not a statistical confidence interval.

Not included: ads, payments outside the App Store, and any difference between gross sales and what the developer keeps. Low confidence means indirect data; medium means several independent sources agree.

Full method

Screenshots

As shown on the App Store listing.

About this app

Text from the App Store listing.

COLREG 72 is a complete study and reference app for the International Regulations for Preventing Collisions at Sea (COLREGs). Designed for maritime students, merchant navy officers, yacht skippers, and anyone preparing for an MCA, RYA, or international maritime examination.

WHAT IS INCLUDED

  • Full text of all 72 COLREG rules (Annexes I through IV)
  • Theory study with illustrations
  • Navigation lights identification quizzes
  • Light placement quizzes — put the lights on the vessel silhouette yourself (74 questions, Rules 23–30)
  • Rule-based tests with answer explanations
  • Exam mode — a timed mock examination across all the rules with a final score and a full mistake review
  • Cross-references between rules and theory — open in popup overlays so you never lose your place

HOW IT WORKS

Theory and rules are linked throughout the app. When you answer a quiz question incorrectly or open a hint, a direct link appears to the exact theory section that covers the topic. Review the rule, then return to the quiz.

The app tracks which theory sections you have read, so you always know where you left off and what still needs attention.

EXAM MODE

Simulate the real examination. The exam is timed and draws questions from across all the rules. When time runs out, you get a clean result screen with your score and every mistake listed. Tap a wrong answer to see the explanation, the original comment from the question card, and a direct link to the relevant rule — so every attempt teaches you something.

READING

Reading is fully customisable: choose from multiple font types, adjust the font size, and switch between three colour themes — light, sepia, and dark — for comfortable study in any lighting condition. Layouts are tuned for both iPhone and iPad.

WHO IT IS FOR

  • Maritime students at nautical colleges and academies
  • Merchant navy officers preparing for OOW, Chief Mate, or Master examinations
  • Yacht skippers and RYA Day Skipper / Yachtmaster candidates
  • Coastal and offshore sailors who need a reliable collision avoidance reference
  • Anyone sitting an MCA, MNI, or international maritime authority examination

WHY COLREG 72

International collision avoidance regulations are the foundation of safe navigation at sea. Whether you are studying for the first time or refreshing your knowledge before an examination, this app gives you the full text, visual aids, practice tests, and a realistic exam mode to build true confidence.

One-time purchase. No subscription. No ads. Study offline, anytime.

Download COLREG 72 and arrive at your examination prepared.

What’s new

Release notes for the latest version, as written by the developer.

v2.8.0

Light Placement Quizzes
A new question type: put the navigation lights on the vessel silhouette yourself — masthead, side and stern lights, special signals. 74 questions across Rules 23–30, with hints, a light-by-light review and a direct link to the rule.

Learn Annex I the practical way: where each light goes, not just what it means.

Rank history

Daily position in the Spain charts. #1 is at the top.

Best rank
#6
Current rank
#42
Days charting
4 of 7

On the charts today

Small & simple score

How realistic it is for a small team to build something like this.

74/100

Not flagged as small & simple

  • Developer size10% · 25

    Developer: 5 apps on the charts

  • Audience size100% · 20

    Ratings: 214

  • App size60% · 10

    Size: 76 MB

  • Price model100% · 15

    Price model: paid

  • Demand proof100% · 30

    Best rank #1, 49 countries

An indicator, not a fact. We can't see team size. Calculated Oct 24, 2026 · method i2

How the score works

Version history

  • 2.8.0LatestReleased Oct 19, 2026
  • 2.7.0Released May 5, 2026