Question 19 MODU01 - Offshore Installation Manager

The Correct Answer is A. **Explanation of Option A (Correct):** The fundamental rule for determining risk of collision is based on the concept of Constant Bearing, Decreasing Range (CBDR). * **Bearing is Constant:** This indicates that the line of sight between your vessel and the other vessel is fixed, meaning if you maintain your course, you will both arrive at the same geographical point simultaneously (a crossing situation or head-on situation, depending on relative position). * **Range is Decreasing:** This confirms that the vessels are closing the distance between them. When a vessel is on your **starboard quarter** (behind your beam, on the starboard side) and exhibits CBDR, it means the other vessel is overtaking you and is set to collide with you if neither vessel alters course. According to the COLREGs (Rules 13 and 7), **risk of collision definitely exists** in this situation. **Why the Other Options are Incorrect:** * **B) A vessel is 22 degrees abaft your port beam, range increasing, bearing is constant.** * While the bearing is constant (suggesting a potential CBDR track), the **range is increasing**. Since the vessels are moving apart, there is no risk of collision. The vessels are diverging. * **C) A vessel is broad on your starboard beam, range decreasing, bearing changing rapidly to the right.** * The range is decreasing (closing), but the **bearing is changing rapidly**. A rapid change in bearing means the vessel is passing well clear of your intended track. Risk of collision does not definitely exist; the vessel appears to be crossing ahead and clear, or turning away from you. * **D) A vessel is 22 degrees on your port bow, range increasing, bearing changing slightly to the right.** * The **range is increasing** (vessels are moving apart), meaning risk of collision does not exist. While the bearing is changing, the primary factor mitigating risk is the increase in range.