Question 39 ONC05 - Master or Mate of LT 200 GRT

The Correct Answer is C 1. **Explanation for C ("four to six seconds") being correct:** Rule 33(b) of the International Regulations for Preventing Collisions at Sea (COLREGs) and the corresponding Inland Rules defines a "prolonged blast" as a blast of from **four to six seconds** duration. This signal is used specifically by power-driven vessels when sounding restricted visibility signals (fog signals), regardless of whether they are making way or stopped but underway (e.g., a power-driven vessel making way through the water uses one prolonged blast every two minutes; a power-driven vessel underway but stopped uses two prolonged blasts every two minutes). 2. **Explanation of why other options are incorrect:** * **A) about one second (Incorrect):** A blast of "about one second" duration is defined as a **short blast** (Rule 33(a)). Short blasts are used in maneuvering and warning signals (Rule 34), not as the primary fog signal for a power-driven vessel. * **B) two to four seconds (Incorrect):** This duration does not correspond to a specific defined blast length (short, prolonged, or intermediate) in the COLREGs/Inland Rules. The specified range for a prolonged blast is 4 to 6 seconds. * **D) eight to ten seconds (Incorrect):** This duration is significantly longer than the defined prolonged blast. It exceeds the regulatory maximum of six seconds and is not a defined blast signal used under the Rules.