What is required to properly interpret another vessel's navigation light pattern?

The correct choice is understanding light color and heading because navigation lights are a crucial part of maritime communication, indicating the size, type, and direction of a vessel. Each color of light has a specific meaning in maritime navigation: red typically indicates port (left) side, green indicates starboard (right) side, and white lights are often used for stern lights. Additionally, the configuration and pattern of these lights inform other vessels of a boat’s orientation and movement, helping to prevent collisions. Therefore, being able to recognize the combination of light colors and their relative positions gives a boater the necessary information to determine the other vessel's heading and behavior in the water.

While knowledge of regional laws can provide context for navigation, and being able to read nautical charts or using a GPS device can enhance overall navigation skills, these do not directly assist in interpreting navigation light patterns. The primary task of identifying another vessel’s intentions relies on understanding what the different colored lights signify and their arrangement, making that knowledge essential for safe navigation at night or in poor visibility conditions.