You are underway on course 172°T at 18.5 knots. The current is 078°T at 2.8 knots. What is the speed being made good?

Correct Answer: Option A — 18.5 knots

Speed made good is the resultant vector of the ship's motion and the current. Using the law of cosines, where the angle between the course (172°) and current (078°) is 94°, the current component along the track is negligible, resulting in a speed made good of 18.5 knots.