Question 35 OSV01 - Master/Chief Mate - Offshore Supply Vessels

The Correct Answer is A **Explanation for A (one prolonged blast):** The Inland Navigation Rules (Rule 34(d)) specifically address the situation of a power-driven vessel leaving a dock or berth. The rule states that a vessel leaving a dock or berth must sound **one prolonged blast** (a prolonged blast is defined as a blast of four to six seconds duration) to signal its intent to other vessels operating nearby. This signal alerts traffic that the vessel is underway and potentially obstructing the channel or fairways. **Why the other options are incorrect:** * **B) four short blasts:** Four short blasts is a common danger or doubt signal used internationally and inland (Rule 34(d)(i) or 34(a)(iii)), but it is not the prescribed signal for simply leaving a dock or berth. * **C) one long blast:** While "one long blast" is often used colloquially, the proper term in the rules is "one **prolonged** blast" (4-6 seconds). Although closely related, in the context of navigation rules questions, the specific terminology ("prolonged") is critical. If A (prolonged) is an option, it is the more precise and technically correct answer than C (long), though sometimes C is used synonymously. In this case, A is the exact regulatory terminology. * **D) no signal is required:** A signal **is** required by the Inland Rules (Rule 34(d)) to ensure safe maneuvering and alert other traffic when leaving a dock or berth.