Question 23 OSV02 - Mate - Offshore Supply Vessels

The Correct Answer is D **Explanation for Option D (Correct):** Option D states the precise rule (Rule 7(b)) used for determining if a risk of collision exists. The criteria outlined in the International Regulations for Preventing Collisions at Sea (COLREGs) and Inland Rules state that such risk shall be deemed to exist if the Compass Bearing of an approaching vessel does not appreciably change. This is often referred to as Constant Bearing, Decreasing Range (CBDR). It indicates that if the angle at which you observe the other vessel remains stable, you are likely on a collision course, and action must be taken. **Explanation of Incorrect Options:** * **A) whenever a vessel crosses ahead of the intended track of another vessel:** While crossing situations require vigilance and may result in risk of collision, crossing the track alone does not definitively confirm the risk exists. The critical factor remains the change in bearing (Rule 7(b)). * **B) if one vessel approaches another so as to be overtaking:** Overtaking situations (Rule 13) are defined by their specific relative directions, but the risk of collision is *always* deemed to exist based on the bearing stability (Rule 7(b)), not merely the geometric relationship of overtaking. Furthermore, the risk may exist even if the vessels are not yet technically defined as overtaking or crossing. * **C) whenever two vessels approach from opposite directions:** Approaching from opposite directions defines a head-on situation (Rule 14), which is a specific type of encounter where risk is presumed, but the *general rule* for determining when risk is deemed to exist, regardless of the geometry, is the constant bearing principle (Rule 7(b)).