What is covered in Rules 20-31?

The correct answer pertains to navigation lights and dayshapes. Rules 20-31 of the International Regulations for Preventing Collisions at Sea (COLREGs) specifically address the requirements for vessels to display appropriate navigation lights and dayshapes to ensure safe navigation and to communicate their status, type, and activities effectively to other vessels. These rules are critical for ensuring visibility and preventing collisions, especially during periods of reduced visibility or at night.

Understanding navigation lights includes recognizing the various colors and configurations of lights displayed by different types of vessels, which indicate their size, type, and the direction they are traveling. Dayshapes are the shapes displayed during daylight hours that also communicate similar information, such as whether a vessel is at anchor, aground, or engaged in fishing. Familiarity with these rules is essential for all mariners to navigate safely and to be aware of the signals displayed by nearby vessels in various circumstances.