🔍 Key Concepts

• Running fix using two bearings (or one bearing and one range) at different times to find your DR error • How to compute set and drift from the difference between dead-reckoned (DR) position and observed position • Converting a distance made good over time into speed in knots using ( \text{Speed} = \frac{\text{Distance (nm)}}{\text{Time (hr)}} )

💭 Think About

• From your DR position at 0740, what course and speed were you intending to make, and where did you expect to be at 0802 if there were no current? • If you plot the two 0802 lines of position (Branford Reef Light and north point of Falkner Island), where is your actual position relative to your DR position? (Direction and distance) • Once you know the direction from DR to actual position and the distance between them, how do you convert that into set and drift over the 22‑minute interval?

✅ Before You Answer

• Be sure you know the time interval between 0740 and 0802 in hours, not minutes, before computing drift • Check that you are measuring the direction of set from DR to observed position, not the other way around • Confirm that your computed drift (knots) is reasonable by using ( \text{Speed (kt)} = \frac{\text{Distance (nm)}}{\text{Time (hr)}} ) and comparing with the answer choices (.2 vs .6 knot)