Question 40 ONC04 - Mate of LT 500-1600 GRT

The Correct Answer is A. **Explanation for Option A (about 1 second):** Option A, "about 1 second," is correct because it defines the duration of a **short blast** in both the International and Inland Rules of the Road (COLREGs/33 CFR). * **Definition:** Rule 32 of COLREGs defines whistle signals: * A **short blast** is a blast of about one second's duration. * A **prolonged blast** is a blast of from four to six seconds' duration. * **Application to Head-on/Crossing Situations:** The maneuvering and warning signals used in head-on and crossing situations (e.g., "I intend to leave you on my port side," or the danger signal) are composed entirely of short blasts (or a series of them, like one short blast, two short blasts, or five or more short blasts). Since the blasts used in these maneuvering signals must be short, their duration is about one second. **Why the other options are incorrect:** * **B) 2 to 4 seconds:** This range does not correspond to any standard, defined whistle signal duration in the Rules. It is too long to be a short blast and too short to reliably meet the definition of a prolonged blast (4-6 seconds). * **C) 4 to 6 seconds:** This range defines a **prolonged blast**. Prolonged blasts are used for specific purposes, such as warning of departure/arrival from a dock (Inland Rule 34(g)) or restricted visibility signals (Rule 35), but they are *not* the basic component used for the maneuvering signals (head-on/crossing situations) defined in Rule 34(a) and 34(c). * **D) 8 to 10 seconds:** This duration is significantly longer than any legally defined signal duration (short blast or prolonged blast) and would be considered an error or a failure to comply with the defined signal lengths.