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Get exam-ready on COLREG, IALA & GMDSS

Study the rules, rotate vessel lights in 3D, listen to sound signals and practise with over 500 questions and explanations.

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All 41 COLREG rules · IALA buoyage · GMDSS · 500+ questions

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Two power-driven vessels in sight meet on reciprocal or nearly reciprocal courses with risk of collision. Under Rule 14, each shall:

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Pick your syllabus. Read the theory, quiz yourself on it, then sit a mock exam when you feel ready.

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Mixed test15 random questions from all three syllabiFull mock exam30 timed practice questions across the three study subjectsReview mistakesGo back over the ones you got wrong

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What's inside

  • Every rule, explained like a person would

    All 41 International COLREG rules and IALA buoyage principles, with official sources linked for reference.

  • Lights you can turn around, sounds you can hear

    Explore selected vessel-light configurations in 3D and listen to whistle, bell and gong examples with COLREG timing.

  • Practice questions with explanations

    Over 500 practice questions with explanations. When device storage is available, your mistakes are saved on this device for review.

Built for the rules part of your exam

Study the International COLREG rules with source texts, explanations, vessel-light models and sound examples. Practise individual topics or use a timed practice exam.

Start wherever you like. Read a rule, take a short quiz on it, then sit a full mock exam when you feel ready. Everything is free to use, supported by a few ads that only appear if you accept them. We're independent, so we don't sell courses or issue licences. We just want you to walk into your exam feeling prepared.

Good to know before you start

Is it really free?
Yes. Every rule, quiz and mock exam is open to everyone, and you never need an account to study. The site is paid for by ads, which only load if you accept cookies. There's no premium tier hiding behind a button.
Will this be enough to pass my exam?
This site supports your study; it does not guarantee a pass or cover every examination syllabus. Check your examining authority's current syllabus and practical training requirements.
Which exams do you cover?
The exam guides explain selected national qualifications. The practice material covers International COLREG, IALA and GMDSS topics; it is an independent study bank, not an official examination bank.
Do you cover the US Inland Rules as well as the international COLREGs?
The rule pages follow International COLREG. U.S. examinations may also require the Inland Rules; consult the USCG texts and the demarcation lines in 33 CFR 80 for their areas of application.
Can I download the rules as a PDF?
Our sources page links official publications and available PDFs. The site adds interactive lights, sound examples and practice questions.