Why is a rhumb line not suitable for long-distance navigation?

The correct choice highlights a key issue with using a rhumb line for long-distance navigation: it can lead to longer travel distances. A rhumb line, which is also known as a loxodrome, represents a path that crosses all meridians at the same angle. While this makes it simple to follow with a compass, it does not result in the shortest distance between two points on the Earth's surface.

The Earth's surface is spherical, and as a result, the shortest path between two points — known as a great circle route — often takes a different course than that of a rhumb line, especially over longer distances. When navigators adhere strictly to a rhumb line trajectory, they inadvertently increase the distance traveled, which can lead to inefficiencies and greater fuel consumption.

Understanding this distinction is crucial for navigational efficiency, particularly during long voyages where optimizing the route can save time and resources. This understanding assists navigators in making informed decisions when charting their courses.