Rule 34(a) · Maneuvering & warning
Three short blasts
“I am operating astern propulsion” — the engines are going astern (which is not the same as actually moving astern).
You hear: 3 short blasts.
Meaning
Internationalyour setting
“I am operating astern propulsion.” Note it signals what the engines are doing, not necessarily that the vessel is moving astern — a ship may still be carrying way forward.
Inland
Same words under Inland Rules, but sounded within the Inland intent-and-agreement exchange used when power-driven vessels meet or cross within half a mile of each other.
Key facts
- Sounded by
- Power-driven vessel underway, in sight of another vessel
- Repeated
- Not a repeating signal — sounded when the situation calls for it
- Applies under
- International & US Inland
- Notation
- · · ·
Related signals
Source: Rule 34(a) — USCG Navigation Rules (International & Inland)
Rule text is reproduced from the public-domain USCG Navigation Rules. Audio is synthesized to Rule 32 timings.