Question 33

The Correct Answer is D. **Why option D ("All of the above") is correct:** The risk of collision in both International (COLREGs Rule 7) and Inland rules is determined by analyzing several indicators, and often, the absence of a clear indicator does not guarantee safety. All three scenarios (A, B, and C) describe conditions where the risk of collision either definitively exists or must be assumed to exist, according to the rules of safe navigation and good seamanship. **Why options A, B, and C are correct indicators of risk (making D the encompassing correct answer):** * **A) even when an appreciable bearing change is evident, particularly when approaching a vessel at close range:** Rule 7(c) specifically states that sometimes an appreciable change in bearing may occur, but risk of collision can still exist, particularly when approaching a very large vessel or a tow, or when approaching a vessel at close range. At close range, small bearing changes can still lead to a collision if speed is high. The rule requires that the navigator take all available action to ensure the absence of risk, not merely rely on bearing change at close proximity. * **B) if you observe both sidelights of a vessel ahead for an extended period of time:** Observing both sidelights (red and green) means you are viewing the vessel dead ahead or nearly so. This scenario is a head-on situation (Rule 14). In a head-on situation, the relative bearing is constant (or nearly constant), and the range is decreasing, which meets the fundamental criterion for risk of collision. The vessels must assume risk exists and take action (both turning to starboard). * **C) if the compass bearing of an approaching vessel does NOT appreciably change:** This is the primary and most common indicator specified in Rule 7(a)(i). If the compass bearing remains constant while the range decreases, a collision course is established, and risk of collision exists. Since A, B, and C are all valid scenarios or conditions under which a risk of collision exists (or must be assumed to exist) under both International and Inland rules, **D (All of the above)** is the correct comprehensive choice. **Briefly explain why each of the other options is incorrect:** As D is the correct answer, A, B, and C are individually incomplete but factually correct statements. They are not "incorrect" indicators of risk, but rather they are reasons why D is the correct answer. * **A) Incorrect as the sole answer:** While a true statement regarding risk at close range, it is not the only condition described. * **B) Incorrect as the sole answer:** While a true indicator of risk (a head-on situation), it is not the only condition described. * **C) Incorrect as the sole answer:** While the primary and classic indicator of risk, it is not the only condition described.