Morse code represents letters and numbers as sequences of short signals (dots) and long signals (dashes) — for over a century, the primary method of long-distance ship communication before voice radio became practical.
Why It’s No Longer Primary
Modern GMDSS uses voice VHF/MF/HF radio and automated digital distress alerting (DSC), which are faster, require no specialist Morse operator skill, and integrate with satellite systems — genuinely superior for routine and emergency communication. Formal commercial Morse code radio requirements were phased out of GMDSS over the 1990s.
Where Morse Code Still Matters
- SOS — three dots, three dashes, three dots (· · · — — — · · ·) remains the single most universally recognized distress signal in the world, understandable regardless of language, and still taught and recognized as a distress indicator
- Visual signaling backup — a signal lamp (Aldis lamp) can send Morse code visually, useful when radio communication has failed or isn’t appropriate, ship-to-ship at reasonably close range
- General maritime literacy — understanding basic Morse, particularly SOS, remains part of standard seafarer safety knowledge even though it’s not the operational primary system
SOS: Why This Specific Pattern
SOS was adopted specifically because its pattern (three short, three long, three short) is simple, unambiguous, and easy to send and recognize even under stress or with imperfect signaling — not because it stands for any specific words, despite common backronyms like “Save Our Souls.”
Exam Relevance
Basic Morse code recognition, particularly SOS, and its historical role relative to modern GMDSS communication is covered within GMDSS and Ship Knowledge topics in deck officer competency exams.