Question 19 FCP01 - First Class Pilot

The Correct Answer is A **Explanation for Option A (Correct Answer):** The fundamental rule for determining risk of collision is based on analyzing the change in bearing and range between the two vessels. According to Rule 7(d)(i) of the COLREGs (International Regulations for Preventing Collisions at Sea), risk of collision shall be deemed to exist if the Compass Bearing of an approaching vessel does not appreciably change. Option A states: "A vessel is on your starboard quarter, **range decreasing, bearing is constant**." 1. **Bearing is constant:** This is the primary indicator of risk of collision. If the bearing does not change, it means the vessels are on a collision course (the CPA, or Closest Point of Approach, is effectively zero). 2. **Range decreasing:** This confirms that the vessels are converging and the CPA will occur in the near future. Therefore, constant bearing and decreasing range unequivocally establish that a risk of collision definitely exists. (Note: While a vessel on the quarter is normally an overtaking situation, the fact that the bearing is constant means a collision course is definitely set, regardless of the relative positions, requiring immediate action.) **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 collision course based on relative velocity vectors), the **range is increasing**. This means the vessel is moving away from you (or its net velocity relative to you is negative), and the CPA has already passed or is never going to occur, meaning there is no current risk of collision. * **C) A vessel is broad on your starboard beam, range decreasing, bearing changing rapidly to the right.** * The **bearing is changing rapidly**. A rapid change in bearing (even with decreasing range) means the CPA is passing ahead or astern of your vessel, indicating that the vessels will safely cross or pass clear. Therefore, risk of collision does not definitely exist. * **D) A vessel is 22 degrees on your port bow, range increasing, bearing changing slightly to the right.** * The **range is increasing**, meaning the vessels are moving apart. * The **bearing is changing**, confirming they are not on a collision course. * Both indicators confirm that there is no risk of collision.