Question 44 ONC04 - Mate of LT 500-1600 GRT

The Correct Answer is D 1. **Explanation for D (Vessel "A" is backing engines) being correct:** The signal of three short blasts (three successive blasts of about one second duration) is defined by Rule 34(a)(iii) of both the International Regulations for Preventing Collisions at Sea (COLREGs) and the Inland Rules (33 CFR § 83.34). This specific maneuvering and warning signal means: **"I am operating astern propulsion"** (i.e., the vessel is backing up or using reverse gear). 2. **Explanation for A (Vessel "A" intends to hold course and speed) being incorrect:** There is no specific whistle signal in the Rules designated solely for indicating an intention to hold course and speed. A vessel maintaining course and speed in a crossing situation is the stand-on vessel, and while they might sound five or more short blasts (danger signal) if the give-way vessel is not acting, three short blasts explicitly indicates a change in propulsion (backing engines). 3. **Explanation for B (Vessel "A" is sounding a signal of doubt) being incorrect:** A signal of doubt or the "danger signal" is defined as five or more short and rapid blasts (Rule 34(d)). Three short blasts has a distinct and different meaning (operating astern propulsion). 4. **Explanation for C (Vessel "A" proposes to cross ahead of the other vessel) being incorrect:** In a crossing situation, a proposal to cross ahead (if allowed and safe) would typically be communicated using one short blast ("I intend to leave you on my port side," applying to power-driven vessels when meeting or crossing in narrow channels/bends, or specifically denoting intent to pass port-to-port in Inland Rules), or two short blasts ("I intend to leave you on my starboard side"). Three short blasts specifically indicates backing engines, not a forward maneuver.