Rule 35(g) · At anchor & aground
Anchored vessel warning (whistle)
One short, one prolonged, one short — an optional whistle warning an anchored vessel may sound at an approaching vessel.
You hear: 1 short blast, then 1 prolonged blast, then 1 short blast.
Meaning
“A vessel at anchor may in addition sound three blasts in succession, namely one short, one prolonged and one short blast, to give warning of her position and of the possibility of collision to an approaching vessel.” It supplements — never replaces — the bell signal.
Key facts
- Sounded by
- Vessel at anchor, in addition to her bell (and gong) signal
- Repeated
- Not a repeating signal — sounded when the situation calls for it
- Applies under
- International & US Inland
- Notation
- · — ·
The vessels that sound this signal also show specific lights and day shapes.
Lights & ShapesRelated signals
Source: Rule 35(g) — USCG Navigation Rules (International & Inland)
Rule text is reproduced from the public-domain USCG Navigation Rules. Audio is synthesized to Rule 32 timings.