At 1423 you are on course 072°T at 12.2 knots, when you sight a rock awash bearing 070°T at a range of 3.6 miles. If you change course at 1427, what course would you steer to leave the rock 1.0 mile abeam to port?

Correct Answer: Option D — 091°

This is a running fix and vector triangle problem in piloting. Plotting the initial position, accounting for set/drift or course change between 1423 and 1427, and solving for the intercept angle leaves the rock 1.0 mile abeam to port on a heading of 091°T.