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Inland · Rule 32

Sound Signal Definitions

Defines whistle, short blast (≈1 sec), and prolonged blast (4–6 sec). 'Whistle' includes any sound-signalling appliance capable of producing the prescribed blasts.

Source: 33 CFR §83.32Last verified 2026-05-16

Rule text#

Source

Verbatim 33 CFR §83.32 as published in the Code of Federal Regulations — public domain, retrieved 2026-05-16.

(a)The wordmeans any sound signaling appliance capable of producing the prescribed blasts and which complies with specifications in Annex III to these Rules (33 CFR part 86).

(b)The termmeans a blast of about 1 second's duration.

(c)The termmeans a blast of from 4 to 6 seconds' duration.

Authoritative source#

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

  • 33 CFR §83.32 — 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 'short blast' on a whistle is a blast of ______.

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Inland Rule 32: Sound Signal Definitions — USCG Captain's Exam Prep · CaptainsGround