Question 20 OSV01 - Master/Chief Mate - Offshore Supply Vessels

The Correct Answer is D **Explanation for D (not impede the passage of vessel "B"):** Vessel "A" is engaged in fishing, which makes it a Vessel Constrained by her Draught (Rule 3(g)). Wait, no, Vessel "A" is a **fishing vessel** (Rule 3(d)). Vessel "B" is a tanker proceeding in a narrow channel, meaning it is likely restricted in its ability to deviate from its course and is required to keep to the starboard side of the channel (Rule 9(a)). Rule 9(b) explicitly states that a fishing vessel (Rule 3(d)) shall not impede the passage of a vessel that can safely navigate only within a narrow channel. Vessel "B" sounding five short and rapid blasts is the danger or doubt signal (Rule 34(d)). This signal indicates that Vessel "B" doubts Vessel "A"'s intentions or is concerned about the risk of collision or the impeding situation. Given that Vessel "A" is obligated *not* to impede Vessel "B*'s passage in a narrow channel, the appropriate action in response to the danger signal is to immediately take action to ensure the passage is not impeded, likely by moving clear of the channel or taking steps to facilitate Vessel "B"'s safe passage. **Explanation of why other options are incorrect:** * **A) maintain course and speed:** This is incorrect. Vessel "B" has sounded the danger signal (five short blasts), indicating doubt or danger. Furthermore, as a fishing vessel in a narrow channel, Vessel "A" has an obligation not to impede Vessel "B" (Rule 9(b)). Maintaining course and speed directly violates the obligation not to impede and ignores the urgent danger signal. * **B) not answer the whistle signals from vessel "B":** This is incorrect. While the five-short-blast signal is not a maneuvering signal requiring a specific response signal (like one short blast for passing), ignoring a danger signal is highly unsafe and violates the requirement to take all necessary action to avoid collision and maintain safe navigation. Vessel "A" must acknowledge the situation by taking appropriate action (i.e., not impeding). * **C) sound one prolonged followed by two short blasts:** This is the signal for a vessel *not* under command or a vessel *restricted* in her ability to maneuver (Rule 35(c)). While a fishing vessel is restricted in its ability to maneuver while fishing, using this signal in response to a danger signal from an approaching vessel would be confusing and inappropriate unless Vessel "A" was genuinely unable to take immediate action. The primary duty here is to move clear (not impede), not to announce status using the R.I.M. signal.