You are underway on course 160°T at 10 knots. The current is 210°T at 0.9 knots. What is the speed being made good?

Correct Answer: Option A — 10.7 knots

Vector resolution of the vessel's motion (160°T, 10 knots) and the set/drift (210°T, 0.9 knots) requires calculating the resultant vector. Using the Law of Cosines, the angle between vectors is 50°. The resultant speed made good is 10.7 knots, accounting for the current's push relative to the heading.