What is the primary function of a compass on a ship?

The primary function of a compass on a ship is to tell you where north is. A compass provides essential navigation information by indicating magnetic north, which helps in determining the ship's heading relative to geographic landmarks or navigational charts. This directional guidance is vital for navigating open waters, avoiding hazards, and ensuring that the vessel remains on its intended course.

Understanding the importance of north is crucial for maritime navigation as it serves as a reference point for all other directions. Without a functioning compass, a ship's crew would find it significantly more challenging to navigate effectively, especially in vast, featureless ocean areas. Functionality like measuring speed, indicating location, or displaying weather conditions are tasks fulfilled by other instruments, underscoring the unique and critical role of the compass in navigation.