Question 39 TV01 - Towing Vessels - Oceans or Near Coastal

The Correct Answer is C. **Explanation for Option C (four to six seconds):** Option C is correct based on the Convention on the International Regulations for Preventing Collisions at Sea, 1972 (COLREGs), Annex III, Section 2(a) and Rule 3(b). * **Rule 3(b)** defines a "prolonged blast" as a blast of from four to six seconds' duration. * **Rule 35(a) and (b)** mandate that power-driven vessels use prolonged blasts as part of their sound signals in restricted visibility (fog). Specifically, a vessel making way through the water must sound one prolonged blast at intervals of not more than two minutes (Rule 35(a)), and a vessel underway but stopped (not making way) must sound two prolonged blasts, with an interval of about two seconds between them, at intervals of not more than two minutes (Rule 35(b)). * Since the question asks for the duration of *each prolonged blast* used by a power-driven vessel in fog, the answer must align with the definition in Rule 3(b): four to six seconds. This definition applies equally to both International and Inland Rules. **Explanation for Incorrect Options:** * **A) about one second:** This duration defines a "short blast" (COLREGs Rule 3(a)). Short blasts are used in maneuvering and warning signals (Rule 34), not as the primary characteristic signal for a power-driven vessel in fog. * **B) two to four seconds:** This range does not correspond to any standard duration defined for a blast signal (short or prolonged) in the COLREGs. * **D) eight to ten seconds:** This duration is significantly longer than the defined "prolonged blast" (four to six seconds) and is not specified for any standard whistle signal in the COLREGs.