Question 15 OSV01 - Master/Chief Mate - Offshore Supply Vessels

The Correct Answer is A **Explanation for A (Neither vessel is the stand-on vessel.) being correct:** The scenario described involves two vessels crossing in fog (restricted visibility) and they are **not in sight of one another**. This situation is governed by Rule 19 (Conduct of Vessels in Restricted Visibility) of both the International Regulations for Preventing Collisions at Sea (COLREGs) and the Inland Rules. Rule 19 supersedes the normal Rules 12, 13, 14, 15, and 17 regarding sailing, overtaking, head-on, and crossing situations, which apply only when vessels are in sight of one another. When vessels detect each other only by sound (fog signals) or radar but are not in sight: 1. **Rule 19(d)** requires any vessel that detects another vessel forward of the beam to determine if a close-quarters situation (risk of collision) is developing. 2. **Rule 19(e)** applies specifically when a risk of collision exists and a vessel hears a fog signal forward of her beam or cannot avoid a close-quarters situation with a vessel forward of the beam. This rule mandates that the vessel shall reduce her speed to bare steerageway or, if necessary, take all way off. She is also required to navigate with extreme caution until the danger of collision is over. Crucially, **Rule 19 does not assign the roles of "give-way" or "stand-on" vessel.** Instead, it mandates specific cautious actions for *both* vessels involved to avoid collision. Therefore, neither vessel has the right-of-way (stand-on status). **Why the other options are incorrect:** **B) The vessel which hears the other vessel's fog signal first:** The order in which a signal is heard has no bearing on assigning stand-on status. COLREGs are based on the geometry of the encounter (head-on, crossing, overtaking) when in sight, or on the presence of restricted visibility (Rule 19), not on who detected the danger first. **C) The vessel which has the other on her own starboard side:** This describes the **give-way vessel** in a crossing situation (Rule 15), but Rule 15 applies only when vessels are *in sight* of one another. Since the vessels are in fog and not in sight, Rule 19 applies, and the normal crossing roles are suspended. **D) The vessel which has the other on her own port side:** This describes the **stand-on vessel** in a crossing situation (Rule 15), but Rule 15 applies only when vessels are *in sight* of one another. Since the vessels are in fog and not in sight, Rule 19 applies, and the normal crossing roles are suspended.