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Inland · Rule 37

Distress Signals

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.

Source: 33 CFR §83.37Last verified 2026-05-16

Rule text#

Source

Verbatim 33 CFR §83.37 as published in the Code of Federal Regulations — public domain, retrieved 2026-05-16.

When a vessel is in distress and requires assistance she shall use or exhibit the signals described in Annex IV to these Rules (33 CFR part 87).

Authoritative source#

Source links checked against the current public rule corpus on 2026-05-16.

  • 33 CFR §83.37 — the section this text comes from, with its neighbours.
  • The Inland Navigation Rules are codified at 33 CFR Part 83 and are public domain. The international COLREGs text is published separately by the IMO.

Practice this rule#

One real exam question on this rule, cited to source. No sign-up.

A passenger vessel certificated for an oceans route operating more than 50 miles from the coastline must carry which distress signal outfit under 46 CFR §28.145?

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All Inland Navigation RulesRule 32 — Sound Signal DefinitionsRule 33 — Equipment for Sound SignalsRule 34 — Maneuvering and Warning SignalsRule 35 — Sound Signals in Restricted VisibilityRule 36 — Signals to Attract AttentionCOLREGs Rule 37Practice Rule 32Practice Rule 34Practice Rule 35Practice: Rules of the Road
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Inland Rule 37: Distress Signals — USCG Captain's Exam Prep · CaptainsGround