Fog, underway, Inland

Fishing or restricted, at anchor

At anchor and sounding the same three-blast signal these vessels use underway.

One prolonged blast, then two short blasts

Press play. One signal at a time.

Fishing or restricted, at anchorInland
At anchor and sounding the same three-blast signal these vessels use underway.
Inland Rule 35(c), 33 CFR 83.35(c)

Who sounds it

Vessel fishing at anchor, or restricted in ability to maneuver at anchor.

How it's sounded

Short blast: about 1 second (Rule 32(b)). Prolonged blast: 4 to 6 seconds (Rule 32(c)); 5 seconds is used here. The rule sets no gap between blasts. 1 second is used here so the blasts stay distinct.

At intervals of not more than 2 minutes.

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

In or near an area of restricted visibility, by day or by night. You don't have to be inside the fog.

Worth remembering

Inland puts this in paragraph (c), and paragraph (d) is reserved. Paragraph (c) replaces the (a) and (b) signals. Unlike International Rule 35(d), it doesn't say it replaces the anchor bell. It also doesn't add International's "when carrying out her work".

The same sound elsewhere

These use the same pattern, so the rules you’re under and the situation decide what it means.

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

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Sources

Inland Rule 35(c), 33 CFR 83.35(c)

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.