What does the plan position indicator show?

The correct response highlights that the plan position indicator (PPI) is primarily designed to display target bearings and area representations. This instrument is a vital tool in navigation, particularly in radar systems, as it provides a visual representation of the surrounding environment, including other vessels, landmasses, and navigational hazards.

By presenting real-time information about the positions and movements of objects relative to the vessel's own position, the PPI enables crew members to make informed decisions regarding navigation and course adjustments. It plays a crucial role in collision avoidance and situational awareness.

In contrast, while other options may pertain to various aspects of vessel operation or environmental conditions, they do not accurately describe the function of the plan position indicator. For instance, the speed of the vessel, physical dimensions, and weather conditions are important factors in navigation but are not shown on the PPI. This visual display specifically focuses on target positions and bearings, making it an essential component for navigating and ensuring safety on the water.