Question 46

The Correct Answer is D. The question asks which vessel(s) are required to sound a fog signal of **one prolonged followed by two short blasts**. This specific signal is detailed in Rule 35(c) (International and Inland), which states: > A vessel **not under command**, a vessel **restricted in its ability to maneuver** (including a vessel engaged in towing which is severely restricted in its ability to deviate from its course), a vessel **constrained by its draft** (International only), a **sailing vessel**, or a fishing vessel, when underway or at anchor (the latter requirement applying only to a vessel restricted in its ability to maneuver and a vessel constrained by its draft), shall instead of the signals prescribed in paragraph (a) or (b) of this Rule, sound at intervals of not more than 2 minutes, **one prolonged blast followed by two short blasts.** Since this signal applies to all the vessel types listed in options A, B, and C, option D ("All of the above") is the correct comprehensive answer. **Why option D ("All of the above") is correct:** * **A) A vessel restricted in its ability to maneuver, at anchor:** Rule 35(c) explicitly applies this signal to a vessel restricted in its ability to maneuver, and the preamble to Rule 35(c) specifically includes vessels restricted in their ability to maneuver *at anchor* for this signal (though some vessel types listed only use this signal when underway). * **B) A sailing vessel underway:** Rule 35(c) explicitly names a sailing vessel as one that must use this signal when underway. * **C) A vessel not under command:** Rule 35(c) explicitly names a vessel not under command as one that must use this signal when underway. **Briefly explaining why each of the other options is incorrect:** Options A, B, and C are incorrect because while they are individually true examples of vessels required to use the one prolonged followed by two short blasts signal, they are not the *only* vessels required to do so. Since all three types listed require this specific signal, the most accurate answer encompassing all the correct choices is D.