Question 23 OSV01 - Master/Chief Mate - Offshore Supply Vessels

The Correct Answer is D **Explanation of Option D (Correct):** Option D states, "if the bearing of an approaching vessel does not appreciably change." This is the nearly verbatim definition provided in Rule 7 (Risk of Collision) of both the International Regulations for Preventing Collisions at Sea (COLREGs) and the Inland Rules. Specifically, Rule 7(a)(i) states that risk shall be deemed to exist if the compass bearing of an approaching vessel does not appreciably change. This principle is the most reliable immediate indicator used by mariners to determine if a collision scenario is developing, regardless of the angle of approach. **Explanation of Incorrect Options:** * **A) whenever a vessel crosses ahead of the intended track of another vessel:** While crossing situations are dangerous and addressed by the Rules (Rule 15), the act of crossing itself does not automatically guarantee a risk of collision exists *unless* the bearing is steady. A vessel may cross far ahead without risk. * **B) if one vessel approaches another so as to be overtaking:** Overtaking is a defined situation (Rule 13), but the rule specifically addresses the *relationship* and responsibilities (the overtaken vessel is the stand-on vessel). Risk of collision is determined by bearing change, not merely the categorization of the approach. An overtaking vessel might be on a track that will pass safely clear, and thus no risk exists. * **C) whenever two vessels approach from opposite directions:** This describes a head-on situation (Rule 14). While head-on approaches usually carry a high risk of collision, the Rules do not state that risk *shall be deemed to exist* simply because the approach is opposite. If the vessels are clearly offset and will pass safely clear (indicated by a changing bearing), risk may not exist.