USCG Exam PracticePlot true course and distance between two charted points
A vessel is steaming on a true course of 045° at 10 knots. A current is setting 180° at 2 knots. Which statement correctly describes the relationship between the vessel's course through the water and its track over the ground?
- A. The course over ground will be identical to the course steered because current only affects speed
- ✓ The vector sum of the course steered and the current vector gives the actual course over groundCorrect
- C. The current vector must be subtracted from the course steered to obtain course over ground
- D. Set and drift affect only the distance run, not the direction of travel
Why B is correct
Bowditch Ch. 23 §2302 states that the vector sum of the intended course through the water and the current vector gives the actual course over ground. Current affects both direction and speed of the track over ground.
Cited:Bowditch Ch. 23 §2302