Question 40

The Correct Answer is A. **Explanation for Option A (about 1 second):** Option A ("about 1 second") is correct because it describes the duration of a **short blast** as defined in the International Regulations for Preventing Collisions at Sea (COLREGs) and the Inland Navigation Rules. * **COLREG Rule 32(a) and Inland Rule 32(a)** define a **short blast** as a blast of about one second's duration. * The whistle signals used to indicate maneuvering intentions in head-on and/or crossing situations (e.g., "I intend to alter course to starboard" – one short blast; "I intend to alter course to port" – two short blasts; "I am operating astern propulsion" – three short blasts) are all composed of these standardized short blasts. **Explanation for Incorrect Options:** * **Option B (2 to 4 seconds):** This duration is incorrect for maneuvering signals. A blast of 4 to 6 seconds (or simply 4–6 seconds in duration) is defined as a **prolonged blast** in both COLREGs and Inland Rules (Rule 32(b)). Prolonged blasts are used for warning signals (e.g., restricted visibility signals, leaving a dock/bend). * **Option C (4 to 6 seconds):** This is the definition of a **prolonged blast**, not a short blast. Prolonged blasts are used primarily for signals of warning or presence (e.g., when approaching a blind bend or operating in fog). They are not the components of the standard head-on/crossing maneuvering signals. * **Option D (8 to 10 seconds):** This duration is significantly longer than any standardized blast (short or prolonged) defined in the COLREGs or Inland Rules and is not used for any official whistle signal.