Question 7 ONC05 - Master or Mate of LT 200 GRT

The Correct Answer is C **Explanation of Correct Answer (C):** Option C states, "You may sound at least five short and rapid blasts on the whistle." This is correct because the scenario describes a situation of doubt regarding the intentions of another vessel (a crossing situation in a narrow channel, but the critical element is the doubt). Rule 9 (Narrow Channels) governs navigation within the channel, but the specific action addressing doubt or risk of collision falls under Rule 34(d) (Maneuvering and Warning Signals) and Rule 7 (Risk of Collision). Rule 34(d) of the **International Regulations for Preventing Collisions at Sea (COLREGs)** mandates that if a vessel approaching another is in doubt as to the intention of the other vessel or is in doubt whether sufficient action is being taken by the other to avoid collision, the vessel in doubt **shall** indicate such doubt immediately by sounding at least five short and rapid blasts on the whistle. This signal is the official warning or "danger signal" indicating disagreement or doubt regarding the safety of the situation. **Explanation of Incorrect Options:** **A) You must sound one prolonged and two short blasts:** This signal (Rule 35(e)) is used by a vessel when **underway and making way** in conditions of restricted visibility (fog, etc.), not as a danger or doubt signal in clear visibility. **B) You should sound one short blast to indicate that you are holding course and speed:** One short blast (Rule 34(a)(i)) indicates "I am altering my course to starboard." It is an **action** signal, not a doubt signal, and holding course and speed does not require a specific sound signal in this crossing situation unless acting as the stand-on vessel and taking action to avoid collision when necessary (Rule 17(a)(ii) and (b)). Using a single short blast here would misleadingly imply a course change. **D) You are required to back down:** While maneuvering to avoid collision (Rule 8) might include reducing speed or stopping/reversing engines, there is no specific rule requiring backing down solely because of doubt about another vessel's intentions. The immediate and specific requirement when in doubt is to sound the warning signal (C), allowing time to assess the situation before maneuvering drastically.