Rule 35(b) · Restricted visibility
Power-driven vessel underway but stopped (fog)
Two prolonged blasts, about 2 seconds apart, every 2 minutes — underway but stopped and making no way through the water.
You hear: 1 prolonged blast, then about 2 seconds of silence, then 1 prolonged blast.
Meaning
“A power-driven vessel underway but stopped and making no way through the water shall sound at intervals of not more than 2 minutes two prolonged blasts in succession with an interval of about 2 seconds between them.” Underway just means not anchored, made fast, or aground — a drifting ship is still underway.
Key facts
- Sounded by
- Power-driven vessel underway but stopped, making no way through the water
- Repeated
- every 2 minutes
- 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(b) — USCG Navigation Rules (International & Inland)
Rule text is reproduced from the public-domain USCG Navigation Rules. Audio is synthesized to Rule 32 timings.