Question 3453 Deck General

The correct answer is A) One prolonged and three short blasts. According to the International Regulations for Preventing Collisions at Sea (COLREGS), a vessel restricted in its ability to maneuver, such as a jack-up drilling unit, must sound the signal of "one prolonged blast followed by three short blasts" when visibility is restricted. This signal is used to indicate the vessel's limited maneuverability and the need for other vessels to take appropriate action to avoid a collision. The other options are incorrect because they do not match the specific signal required by the COLREGS for a vessel restricted in its ability to maneuver under restricted visibility conditions.