Question 39 ONC01 - Master/Chief Mate Unlimited Tonnage

The Correct Answer is C. 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, is defined by the **International Regulations for Preventing Collisions at Sea (COLREGs)**. Rule 32 defines a "prolonged blast" as a blast of from **four to six seconds** duration. This definition applies universally to both International (at sea) and Inland (upon navigable waterways) applications where COLREGs are enforced, provided that the Inland rules have adopted this standard (which they generally have for signaling definitions). The other options are incorrect for the following reasons: * **A) about one second:** This duration defines a **short blast** (approximately one second), which is used for maneuvering signals (like "I am altering my course to starboard") but is not the duration for the required fog signals (prolonged blasts). * **B) two to four seconds:** This range is too short. While two seconds is longer than a short blast, it does not meet the minimum four-second requirement for a prolonged blast as defined in Rule 32. * **D) eight to ten seconds:** This range is too long. While it would certainly be noticeable, it exceeds the maximum defined duration of six seconds for a prolonged blast.