COLREGs · Rule 37
Distress Signals
Last verified: 2026-05-16
TL;DR
Annex IV lists the distress signals: SOS, MAYDAY voice, NC flag hoist, square-flag-and-ball, continuous fog horn, gun fired at one-minute intervals, red star rockets, parachute red flare, hand red flare, orange smoke, slow-and-repeated arm raise/lower, EPIRB, DSC alert.
Authoritative source
Source links checked against the current public rule corpus on 2026-05-16.
- 33 CFR §83.37— verbatim Inland Rule text (US Code of Federal Regulations)(retrieved 2026-05-16)
- International COLREGs Rule 37 verbatim text is published by the IMO. The Inland counterpart 33 CFR §83 chunk above mirrors the international wording almost verbatim.
Inland parallel
Inland Rule 37 — Distress Signals →More from Part D — Sound and Light Signals
Related drills
Drill COLREGs Rule 37
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