Question 19 RVR05 - Master of LT 100 GRT

The Correct Answer is C 1. **Why option C ("four to six seconds") is correct:** Rule 33 of the International Regulations for Preventing Collisions at Sea (COLREGs), which applies to both international and inland waters (when adopted), defines "prolonged blast" in the context of sound signals. The definition states that a prolonged blast is a blast of **four to six seconds' duration**. This specific duration is required for signals such as those given by a power-driven vessel operating in or near an area of restricted visibility (fog, mist, etc.). 2. **Why the other options are incorrect:** * **A) about one second:** This duration defines a "short blast," which is used in maneuvering and warning signals (e.g., when vessels are in sight of one another), not for the periodic fog signals of a power-driven vessel. * **B) two to four seconds:** While close to the lower limit, this range does not encompass the full, mandated duration of a prolonged blast (4–6 seconds). * **D) eight to ten seconds:** This duration is significantly longer than the legally defined "prolonged blast" and is not the standard length for any defined whistle signal under COLREGs.