Question 7 ONC01 - Master/Chief Mate Unlimited Tonnage

The Correct Answer is C **Explanation for Option C (Correct Answer):** Option C states, "You may sound at least five short and rapid blasts on the whistle." This is correct because it addresses the situation where a vessel is in doubt as to the intentions or actions of another vessel, which is described in the scenario ("you are in doubt as to his intentions"). According to the International Regulations for Preventing Collisions at Sea (COLREGs), specifically **Rule 34(d)** (Maneuvering and Warning Signals), when vessels are in sight of one another, if the actions of the other vessel are not understood or the vessel is in doubt as to whether sufficient action is being taken by the other vessel to avoid collision, the vessel in doubt **shall indicate such doubt by giving at least five short and rapid blasts** on the whistle (the danger signal). Although the question specifically mentions Rule 9 (Narrow Channels), Rule 9 itself dictates conduct *within* the channel (staying within boundaries, avoiding hindering large vessels, etc.). The *warning signal* used when doubt arises about another vessel's intentions, even if Rule 9 is applicable, is governed by Rule 34(d). **Explanation of Incorrect Options:** **A) You must sound one prolonged and two short blasts:** This signal is designated under Rule 35 (Sound Signals in Restricted Visibility) and indicates a vessel *not under command*, a *vessel restricted in her ability to maneuver*, or a *sailing vessel* when making way through the water. It is not the signal for expressing doubt about another vessel's intentions in clear visibility. **B) You should sound one short blast to indicate that you are holding course and speed:** A single short blast in international waters signifies "I am altering my course to starboard." It is an action signal, not a danger or doubt signal, and holding course and speed (which may be dangerous in this scenario) requires no sound signal unless used in conjunction with a passing or overtaking maneuver, which is not the primary issue here. Using a single short blast when in doubt would be confusing and potentially illegal. **D) You are required to back down:** While taking proper action to avoid collision is mandatory (Rule 8), the first required immediate step when in doubt, especially concerning the other vessel's actions, is to signal that doubt using the danger signal (five short blasts). Backing down (or taking any specific evasive maneuver) is a maneuver governed by the need to avoid collision, but it is not the *required signal* when doubt arises, nor is it the only possible action.