Question 39 OSV02 - Mate - Offshore Supply Vessels

The Correct Answer is C 1. **Why option C ("four to six seconds") is correct:** Rule 33(b) of the International Regulations for Preventing Collisions at Sea (COLREGs) and the corresponding Inland Rules defines the specifications for sound signals. A "prolonged blast" is defined as a blast of from **four to six seconds** duration. This definition applies universally to all vessels required to use such signals, including a power-driven vessel making way or underway but stopped in fog, whether under the International or Inland Rules. 2. **Why the other options are incorrect:** * **A) about one second:** This duration is the definition of a "short blast," which is used in maneuvering and warning signals (Rule 32(b)). * **B) two to four seconds:** This duration falls between a short blast and a prolonged blast and does not correspond to a specifically defined signal duration in COLREGs or Inland Rules. * **D) eight to ten seconds:** This duration is significantly longer than the defined prolonged blast (4–6 seconds). While vessels may hold a whistle for slightly longer in practice, the legally defined maximum duration for a prolonged blast is six seconds.