Light signals, Inland

Maneuvering light signals

One flash: I intend to leave you on my port side. Two flashes: I intend to leave you on my starboard side. Three flashes: operating astern propulsion. Five or more short and rapid flashes may back up the danger signal.

Who sounds it

A vessel may add them to its whistle signals.

How it's sounded

Each flash about 1 second (Rule 34(b)(ii)). No interval between flashes or signals is set.

A short blast is about 1 second. A prolonged blast is 4 to 6 seconds. Clips use 1 and 5 seconds.

Worth remembering

Optional. The light, if fitted, is all-round white or yellow, visible at least 2 miles, and synchronized with the whistle.

Study more

See every sound signal, try the free Rules of the Road practice test, or read who gives way, and how Inland differs.

Learn the whole set

Helm drills every signal with flashcards and spaced review, on the web and iPhone.

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Sources

Inland Rule 34(b), Rule 34(d), 33 CFR 83.34(b)

Helm is an independent study aid, not affiliated with or endorsed by the U.S. Coast Guard or the National Maritime Center. This page is for study, not navigation guidance or legal advice. Check the current rules before you rely on anything here.