Question 35 ONC04 - Mate of LT 500-1600 GRT

The Correct Answer is A **Explanation for A (one prolonged blast):** According to the U.S. Inland Navigational Rules (specifically Rule 34(d)), a power-driven vessel, when leaving a dock or berth, is required to sound a signal of **one prolonged blast** (a prolonged blast is defined as a blast of four to six seconds duration). This signal serves to alert other vessels to its presence and maneuvering intention as it moves away from a fixed position and enters the navigable channel. **Why the other options are incorrect:** * **B) four short blasts:** A sequence of four short blasts is used as a danger or uncertainty signal (Rule 34(d)) or, in certain contexts (like restricted visibility), specific maneuvering signals, but not the required signal for leaving a dock or berth. * **C) one long blast:** While "long" and "prolonged" are sometimes used interchangeably in colloquial speech, the precise term mandated by the rules for this specific maneuver is **prolonged blast** (4-6 seconds). "One long blast" is also the required signal for a vessel approaching a bend or obstruction (Rule 34(e)). While the sound might be similar, the correct terminology and specific rule application for leaving a dock/berth is "one prolonged blast." * **D) no signal is required:** A signal **is** required for leaving a dock or berth to satisfy the requirement to announce movement into the channel and ensure the safety of navigation.