Question 44 ONC01 - Master/Chief Mate Unlimited Tonnage

The Correct Answer is D. **Why Option D ("Vessel "A" is backing engines") is correct:** According to both the International Regulations for Preventing Collisions at Sea (COLREGs) Rule 34(c) and the Inland Rules (Rule 34(a)(iii)), a sound signal consisting of **three short blasts** signifies that the vessel is operating astern propulsion (backing engines). This signal is used when the vessel is reversing its engine power, whether moving astern or using the astern power to check headway. **Why the other options are incorrect:** * **A) Vessel "A" intends to hold course and speed:** This is not a standard whistle signal in the maneuvering and warning signals defined by the rules. The vessel usually maintains course and speed unless it signals a maneuver. * **B) Vessel "A" is sounding a signal of doubt:** A signal of doubt (or danger signal) consists of **five or more short blasts**. Three short blasts specifically indicate backing engines. * **C) Vessel "A" proposes to cross ahead of the other vessel:** A vessel signaling a proposed maneuver (like crossing ahead, which usually involves altering course to port or starboard in a crossing situation) would use one short blast (I intend to leave you on my port side) or two short blasts (I intend to leave you on my starboard side) in a passing or meeting situation under Inland Rules (or one short blast for altering course to starboard or two for altering course to port in International Rules, though the context here is backing engines, not proposing a crossing). Three short blasts specifically denotes astern propulsion, not an intention to cross ahead.