🔍 Key Concepts

• Running fix using a DR track between sights • Using Speed = Distance / Time to find distance run in 30 minutes at 18.2 knots • Converting motion along a true course into changes in latitude and longitude in the correct hemisphere

💭 Think About

• How far along the 321°T track will the vessel travel between 0430 and 0500 at 18.2 knots, and in what general direction (toward higher or lower latitude and longitude)? • From your 0430 DR position, if you project your track for 30 minutes, what approximate new latitude and longitude would you expect before applying any sight lines? • Looking at the four choices, which options match the expected general movement in latitude (more north or south) and longitude (more east or west) along course 321°T from the given starting point?

✅ Before You Answer

• First compute the distance run in 0.5 hours at 18.2 knots, then break it into north-south and east-west components if needed. • Check which answers show a change in latitude and longitude that is consistent with course 321°T from 29°56.7'S, 139°11.0'E (i.e., are you moving toward the equator or away from it? toward 140°E or 138°E?). • Verify that the final position should not be too far from the DR position for 30 minutes of run at 18.2 knots; eliminate answers with unrealistically large shifts.