Question 39
OSV01BOTH INTERNATIONAL & INLAND Which is the duration of each prolonged blast on whistle signals used by a power-driven vessel in fog, whether making way or underway but not making way?
AI Explanation
The Correct Answer is C
1. **Explanation for Option C ("four to six seconds"):**
The Rules of the Road (specifically, COLREGs Rule 32 and associated Annex III, Section 1(a)) define the characteristics of sound signals. A "prolonged blast" is defined as a blast of **four to six seconds' duration**. This definition applies universally under both the International and Inland Rules for any vessel required to use this specific signal component (such as the fog signals for a power-driven vessel).
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 (Rule 34), not as the duration for a prolonged blast in fog (Rule 35).
* **B) two to four seconds:** This range is too short. While it overlaps slightly with the required lower limit, it does not match the official regulatory definition (4–6 seconds).
* **D) eight to ten seconds:** This duration is too long. While the rules do not strictly prohibit very long blasts, the defined prolonged blast used in mandatory fog signals must fall within the 4-to-6 second range.