Lanterna – COLREG, IALA, Morse

Lanterna is a study app for deck cadets and watchkeepers, made by a master mariner. It trains the parts of the exam that are hard to learn from a book: recognising a vessel by her lights at night, knowing what to do when another ship is closing, and using the right words on the VHF.

Every picture is drawn by the app from the rules, in changing light, angles and scenery – so you learn to recognise the real thing, not one picture. Every answer comes with the rule behind it.

WHAT YOU CAN STUDY
• Lights & shapes – identify vessels by their lights at night and their shapes by day, from every angle (COLREG Rules 21–31)
• COLREGs – "what do you do?" situations: crossing, head-on, overtaking, who gives way to whom, and restricted visibility on radar (Rule 19)
• IALA buoyage – lateral, cardinal and other marks in Region A and B, sector lights, and light characters you time with a stopwatch
• Sound signals – manoeuvring, warning and fog signals, with sound or as pictures
• Flags & signals – the letter flags and the single-letter signals of the International Code
• Distress & GMDSS – Annex IV signals, MAYDAY, PAN-PAN and SÉCURITÉ, DSC, EPIRB and SART
• VHF & SMCP – the IMO Standard Marine Communication Phrases, message markers, the phonetic alphabet, and wheel and engine orders
• Chart symbols – wrecks, rocks, lights and abbreviations from INT 1
• Morse code – read and send, by dots and dashes or by flashing light, with a signals practice test (free)
• Final exam – the categories you choose, mixed and on time

HOW YOU STUDY
• Flashcards to learn, practice with an explanation after every answer, or a timed test
• Choose the answer, or now and then type it yourself – small spelling mistakes are forgiven
• "My mistakes" brings back what you got wrong until you know it
• Match pairs for quick rounds
• Works offline – study on board without a connection
• IALA Region A or B, light and dark theme

WHO IT IS FOR
• Deck cadets preparing for STCW watchkeeping (OIC-NW) exams
• Officers preparing for a promotion, a revalidation or an oral exam, such as the MCA oral Part A or the 2nd Mate orals
• Yacht skippers studying for Day Skipper, Yachtmaster or a national skipper licence

TRY IT FREE, THEN PAY ONCE
Morse code is free, and every other category has a free round of 10 questions. Everything is then unlocked with a single in-app purchase – no subscription, no ads and no account. Only anonymous usage statistics, never personal data.

Found a question that looks wrong? Report it straight from the question – every report is read.

Lanterna is independent and not affiliated with the IMO, IALA, the MCA, the RYA or any maritime authority.