Question 39

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) governs sound signals in restricted visibility (fog). A "prolonged blast" is defined in Annex III, Section 1(c) of COLREGs as a blast having a duration of **four to six seconds**. This definition applies universally to all vessels requiring the use of a prolonged blast, including the signals given by a power-driven vessel when making way (Rule 35(a)) or underway but stopped (Rule 35(b)). 2. **Why each of the other options is incorrect:** * **A) about one second:** This duration defines a "short blast," not a prolonged blast. A power-driven vessel uses a short blast (or a series of them) for maneuvering and warning signals (Rule 34), not as the primary characteristic signal in fog. * **B) two to four seconds:** While close to the lower limit, this range does not encompass the full duration defined for a prolonged blast (four to six seconds) according to COLREGs. * **D) eight to ten seconds:** This duration is too long for a standard whistle signal and does not correspond to the internationally defined duration of either a short or a prolonged blast.