Question 36 RVR01 - Master of Unlimited Tonnage

The Correct Answer is A. **Explanation for Option A (about 1 second):** Option A ("about 1 second") is correct because it accurately describes the duration of a **short blast** of the whistle signal as defined by the International Regulations for Preventing Collisions at Sea (COLREGs) and Inland Rules. The maneuvering and warning signals used in head-on and/or crossing situations (Rules 34 and 35) utilize short blasts. * **Rule 3(i) (Definitions):** COLREGs defines a "short blast" as a blast of about one second's duration. * **Application:** Signals such as "I intend to alter course to starboard" (one short blast) or "I am operating astern propulsion" (three short blasts) rely entirely on this specific, short duration to be correctly interpreted. Since the question asks about signals used in head-on and/or crossing situations, it refers to these maneuvering signals. **Why other options are incorrect:** * **B) 2 to 4 seconds:** This duration is too long for a short blast. While a **prolonged blast** is defined as 4 to 6 seconds (see C), 2 to 4 seconds falls between the definitions of a short and a prolonged blast and is not a defined signal duration for maneuvering. * **C) 4 to 6 seconds:** This duration defines a **prolonged blast** according to COLREGs (Rule 3(j)). A prolonged blast is used for general warnings (e.g., restricted visibility signals, leaving a dock) but is not the duration specified for the individual blasts within the maneuvering signals used in head-on or crossing situations. * **D) 8 to 10 seconds:** This duration is significantly longer than any defined standard blast (short or prolonged) used in whistle signaling under COLREGs or Inland Rules.