Question 19 RVR04 - Master or Mate of LT 200 GRT

The Correct Answer is C 1. **Why option C ("four to six seconds") is correct:** Rule 32(b) of the International Regulations for Preventing Collisions at Sea (COLREGs) defines a "prolonged blast" as a blast of from four to six seconds' duration. The sound signals used by a power-driven vessel operating in or near an area of restricted visibility (fog, mist, etc.)—whether making way through the water (Rule 35(a)) or underway but stopped and not making way (Rule 35(b))—rely on this specific duration for the prolonged blast. 2. **Why the other options are incorrect:** * **A) about one second:** This duration defines a "short blast" (Rule 32(b)). A short blast is used in maneuvering and warning signals (Rules 34 and 35(c), (d)) but not as the primary characteristic of the standard fog signals for power-driven vessels. * **B) two to four seconds:** This duration falls outside the defined range for either a short blast (one second) or a prolonged blast (four to six seconds) according to COLREGs Rule 32(b). * **D) eight to ten seconds:** This duration is significantly longer than the defined limit for a prolonged blast (maximum of six seconds) and is not specified for any standard whistle signal under COLREGs.