Question 406 Rules of the Road

The correct answer is D) One prolonged, one short, one prolonged, and one short blast. This signal is used to indicate your agreement with the overtaking vessel's intention to pass on your starboard side, as per Rule 34(c) of the International Regulations for Preventing Collisions at Sea (COLREGS). The overtaking vessel has already sounded the proper signal to indicate its intention, and you are responding with the appropriate acknowledgment signal. The other options are incorrect because they do not match the specific signal prescribed by the COLREGS for this situation. A and B are different sound signals used for different purposes, while C does not include the full sequence of one prolonged, one short, one prolonged, and one short blast.