Question 40 ONC01 - Master/Chief Mate Unlimited Tonnage

The Correct Answer is A. ### Explanation for Option A (Correct Answer) Option A, "about 1 second," is correct because the whistle signals used to indicate maneuver intention in head-on and/or crossing situations are defined under both the International Regulations for Preventing Collisions at Sea (COLREGs Rule 34) and the Inland Navigation Rules. The duration of these signals—a **short blast**—is defined as: * **Rule 34(a) (Inland and International):** "When vessels are in sight of one another, a power-driven vessel intending to maneuver must indicate that maneuver by whistle signals..." * **Rule 32(b) (Definitions):** A "short blast" is a blast of about one second's duration. Therefore, the signals used (one, two, or three short blasts) must each last **about 1 second**. ### Explanation for Other Options (Incorrect) * **B) 2 to 4 seconds:** This duration falls within the range of a **prolonged blast** (defined as 4 to 6 seconds), or a sequence of short blasts, but it is not the standard duration for a single intentional maneuvering signal (short blast). * **C) 4 to 6 seconds:** This is the precise duration of a **prolonged blast** (defined as a blast of 4 to 6 seconds). Prolonged blasts are used primarily as warning signals (Rule 34(b) - the one prolonged blast signal when maneuvering out of a bend or approaching a blind area) and as part of restricted visibility signals (Rule 35), not for the individual blasts used in head-on or crossing intentional maneuvering signals. * **D) 8 to 10 seconds:** This duration is significantly longer than any standard prescribed whistle blast (short or prolonged) and is not used for defined navigational signaling.