Question 502 Rules of the Road

The correct answer is D) Whistle only. According to the International Regulations for Preventing Collisions at Sea (COLREGS) and the Inland Navigation Rules, a vessel 13 meters (approximately 42.6 feet) in length is required to have a whistle as the only mandatory fog signal equipment. Vessels of this size are not required to have a bell or gong for fog signals. The other options are incorrect because they either include additional equipment (bell or gong) that is not mandated for a 13-meter vessel, or they omit the whistle, which is the sole fog signal requirement for a vessel of this size.