What emergency equipment is required for every vessel according to the COLREGs?

The correct choice emphasizes that emergency flares and distress flags are essential equipment required for every vessel according to maritime safety regulations. These items serve as critical tools for signaling distress to nearby vessels or coastal authorities. When a vessel is in trouble, using flares and flags can effectively communicate an emergency situation, alerting others to provide assistance as needed.

While safety vests and life rafts contribute to a vessel's overall safety, they are not specifically mandated by COLREGs as essential pieces of emergency signaling equipment. Similarly, first-aid kits and navigational charts play important roles in safety and navigation, but they do not directly serve the purpose of distress signaling. Weather radar and sonar equipment, although valuable for navigation and weather assessment, are not categorized as emergency signaling devices required by the COLREGs. Thus, emergency flares and distress flags are recognized as critical for informing nearby vessels of a distress situation, aligning with the COLREGs' focus on ensuring safe navigation and effective communication at sea.