In navigation, both True Course (TC) and True Heading (TH) refer to the direction of travel of a vessel or aircraft, but they are slightly different concepts:
- True Course (TC):
- The True Course refers to the planned or intended direction of travel, expressed in degrees relative to True North (the geographic North Pole). It is the direction in which the vessel or aircraft is supposed to move across the Earth’s surface.
- For example, a True Course of 90° means the vessel is traveling directly east, considering the geographic north as the reference.
- True Heading (TH):
- The True Heading refers to the actual direction in which the vessel or aircraft is facing at any given moment. This is also measured in degrees relative to True North.
- The True Heading reflects the orientation of the vessel or aircraft, which may differ from the True Course due to factors like wind, currents, or other external influences. Essentially, the True Heading describes the direction the vessel is pointing at, which may not always align with the planned True Course.
Relationship Between True Course and True Heading:
- True Course (TC) is the planned direction of travel to reach a destination, based on geographic coordinates and navigation charts.
- True Heading (TH) is the actual direction the vessel or aircraft is facing or following at any moment, which may differ from the True Course due to environmental factors (such as wind or current).
Example:
- If the True Course (TC) is 90°, this means the vessel is supposed to travel due east according to geographic north.
- However, the True Heading (TH) may be 85° because the vessel could be pushed off course by a wind or current, causing the actual direction it is pointing to differ slightly from the intended course.
In summary, True Course (TC) is the intended or planned direction, while True Heading (TH) is the actual direction the vessel or aircraft is facing.
