Question 45 ONC01 - Master/Chief Mate Unlimited Tonnage

The Correct Answer is B **Explanation for Option B (One prolonged blast):** The rule governing maneuvering in restricted visibility or at bends where visibility is obstructed is primarily found in the **COLREGs (International Regulations for Preventing Collisions at Sea)**, specifically Rule 34(e) (for Inland/International). This rule, and its corresponding requirement in Inland rules (often 34(e) as well, or similar state/local rules), mandates that a power-driven vessel, when nearing a bend or an area of a channel or fairway where other vessels may be obscured by an intervening obstruction, must sound one prolonged blast. This signal serves as a cautionary warning to any vessel that may be on the other side of the obstruction, alerting them to the vessel's approach. A prolonged blast is defined as a blast of 4 to 6 seconds duration. **Explanation for Incorrect Options:** * **A) One short blast:** This signal (about 1 second duration) is used internationally and domestically to indicate a maneuvering intention when two vessels are in sight of one another ("I intend to leave you on my port side" or "I am altering my course to starboard"). It is not the required signal for approaching a blind bend. * **C) Two short blasts:** This signal indicates the intention to maneuver by altering course to port ("I intend to leave you on my starboard side" or "I am altering my course to port"). Like one short blast, it is a close-quarters maneuvering signal, not the proper warning signal for a blind bend. * **D) One long blast:** The term "long blast" is generally not a defined sound signal within COLREGs. While a prolonged blast is defined (4–6 seconds), "long blast" is non-standard terminology and could cause confusion. Furthermore, if interpreted as a prolonged blast, it would be correct, but the standard and defined term used in the rules is **prolonged blast**. If interpreted as a generic term different from "prolonged blast," it is incorrect. The signal required is specifically defined as one prolonged blast.