What is the purpose of a boat's compass?

The primary purpose of a boat's compass is to provide directional guidance while navigating. The compass uses the Earth's magnetic field to indicate the direction of magnetic north, allowing a navigator to determine the boat's heading and make adjustments to follow a desired course. This is essential for safe navigation, especially when out of sight of landmarks or in open waters.

A compass is a fundamental navigational tool, as it helps mariners understand their orientation in relation to the cardinal directions, aiding in route planning and ensuring that they can steer towards their destination accurately. It is crucial for effective navigation in both coastal and offshore environments where visual cues may be limited.

The other options serve different functions not related to the primary role of a compass. For instance, measuring speed and monitoring battery voltage are tasks managed by other instruments like speedometers and voltmeters, while fuel level indicators specifically measure the amount of fuel in the tank.