Question 19 TV01 - Towing Vessels - Oceans or Near Coastal

The Correct Answer is A A risk of collision definitely exists when a vessel is on a **constant bearing** and **decreasing range (CBDR)**. This rule is explicitly defined in Rule 7(b) of the International Regulations for Preventing Collisions at Sea (COLREGs), which states that such an observation indicates that a risk of collision exists. **Explanation of Option A (Correct):** A vessel on your starboard quarter, range decreasing, bearing is constant. * **Bearing is constant:** This satisfies the "constant bearing" requirement. * **Range is decreasing:** This satisfies the "decreasing range" requirement. If the bearing remains constant while the range decreases, the two vessels are on a collision course. While a vessel on the quarter (between 4 points abaft the beam and the stern) is typically an overtaking vessel (Rule 13), the fact that the bearing is constant and the range is decreasing means that, regardless of the vessel's initial relative position, the path geometry confirms a collision will occur if no action is taken. **Explanation of Other Options (Incorrect):** * **B) A vessel is 22 degrees abaft your port beam, range increasing, bearing is constant.** * While the bearing is constant, the **range is increasing**. If the range is increasing, the vessels are moving away from each other, and no risk of collision exists. * **C) A vessel is broad on your starboard beam, range decreasing, bearing changing rapidly to the right.** * The **bearing is changing**. If the bearing is changing (especially rapidly), it means the vessel's relative position is shifting significantly, indicating the vessel will likely pass clear. While the range is decreasing, the changing bearing negates the immediate collision risk signal. * **D) A vessel is 22 degrees on your port bow, range increasing, bearing changing slightly to the right.** * The **range is increasing** (moving away), and the **bearing is changing**. Both factors indicate that no risk of collision exists.