Question 39 MODU01 - Offshore Installation Manager

The Correct Answer is C 1. **Explanation for Option C ("four to six seconds"):** The duration of a *prolonged blast* is defined by Rule 32(b) of the International Regulations for Preventing Collisions at Sea (COLREGs), which applies to both International and Inland waters (as the Inland Rules generally mirror COLREGs for whistle signals). Rule 32(b) explicitly states that a prolonged blast is a blast of **four to six seconds** duration. This is the characteristic signal used by a power-driven vessel to indicate its presence in or near an area of restricted visibility (fog, mist, etc.), whether making way or not making way. 2. **Explanation of Incorrect Options:** * **A) about one second:** This duration defines a **short blast** (Rule 32(a)), which is used for maneuvering and warning signals (e.g., "I am altering my course to starboard"). It is not the duration for a prolonged blast used in fog. * **B) two to four seconds:** This range is too short for a standard prolonged blast and does not match the regulatory definition of 4–6 seconds. * **D) eight to ten seconds:** This duration is too long. While a single prolonged blast must last 4–6 seconds, a signal composed of multiple short and prolonged blasts (such as the restricted visibility signal for a vessel being towed or a sailing vessel) may last longer overall, but the duration of the *individual prolonged blast* is strictly 4–6 seconds.