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) and the corresponding Inland Navigation Rules define the characteristics of sound signals. A "prolonged blast" is defined specifically as a blast of from **four to six seconds** duration. This is the signal used by a power-driven vessel (in or near an area of restricted visibility) when: * Making way through the water (one prolonged blast every two minutes). * Underway but stopped and not making way through the water (two prolonged blasts, separated by about two seconds, every two minutes). 2. **Why each of the other options is incorrect:** * **A) about one second:** This duration is defined as a "short blast" (approximately one second). Short blasts are typically used for maneuvering and warning signals (e.g., "I am altering my course to starboard"). * **B) two to four seconds:** This duration does not correspond to any standard, defined whistle signal (short, prolonged, or intermediate) used for fog or maneuvering signals under COLREGs. * **D) eight to ten seconds:** This duration is too long for the defined "prolonged blast" (which is four to six seconds). While eight to ten seconds is a common time interval between the two short blasts of the "danger signal" (five or more short blasts), it is not the duration of a single prolonged blast.