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COLREGs · Rule 20

Application (Lights and Shapes)

Lights are exhibited from sunset to sunrise and in restricted visibility. Shapes are exhibited by day. Annex I governs the technical particulars.

Source: 33 CFR §83.20 · COLREGs Rule 20Last verified 2026-05-16

Rule text#

Source

The international COLREGs text is published by the IMO and is not available to reproduce here. Shown below is the U.S. counterpart, 33 CFR §83.20, which tracks the international wording closely.

(a)Rules in this subpart (Rules 20-31) (§§ 83.20 through 83.31) shall be complied with in all weathers.

(b)The Rules concerning lights (§§ 83.20 through 83.31) shall be complied with from sunset to sunrise, and during such times no other lights shall be exhibited, except such lights as cannot be mistaken for the lights specified in these Rules or do not impair their visibility or distinctive character, or interfere with the keeping of a proper lookout.

(c)The lights prescribed by these Rules shall, if carried, also be exhibited from sunrise to sunset in restricted visibility and may be exhibited in all other circumstances when it is deemed necessary.

(d)The Rules concerning shapes shall be complied with by day.

(e)The lights and shapes specified in these Rules shall comply with the provisions of Annex I of these Rules (33 CFR part 84).

(f)A vessel's navigation lights and shapes may be lowered if necessary to pass under a bridge.

Authoritative source#

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

  • 33 CFR §83.20 — the section this text comes from, with its neighbours.
  • International COLREGs Rule 20 verbatim text is published by the IMO and is authoritative for international waters.

Practice this rule#

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Under 46 CFR §11.302, a seafarer who cannot demonstrate 1 year of sea service within the last 5 years to maintain basic training (BT) competence is required to do which of the following?

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COLREGs Rule 20: Application (Lights and Shapes) — Captain's Exam Prep · CaptainsGround