Question 437 Rules of the Road

The correct answer is A) A cylinder. The International Regulations for Preventing Collisions at Sea (COLREGS) state that a vessel displaying three all-round red lights in a vertical line at night is a vessel "not under command." During the day, such a vessel must display a shape consisting of a cylinder. The other options are incorrect because they do not match the dayshape required for a vessel displaying three vertical red lights at night. Two diamonds, two cones, or three balls would indicate different light configurations or vessel statuses under the COLREGS.