🔍 Key Concepts

• Running fix position from multiple lines of position (LOPs) advanced or retired to a common time • Using DR (dead reckoning) track to advance the earlier sights to the running fix time (course and speed made good) • How small changes in track over several hours affect final latitude and longitude by comparing DR shift against observed lines of position

💭 Think About

• First, from the 1400 DR position, compute the DR position at each sight time and at 1900 using course 023°T and 18 knots. How far have you traveled between each time? • Think about how you combine three LOPs taken at slightly different times into a single running fix: which LOPs are advanced or retired, and by how many miles along the DR track? • After sketching or plotting the three LOPs and advancing/retiring them to 1900, which answer choice best matches the final plotted running-fix position relative to your 1900 DR: is it slightly to the left/right or ahead/astern of the DR track?

✅ Before You Answer

• Be sure your time intervals (in minutes) from 1400 to each sight time and to 1900 are correct before converting to distance run at 18 knots. • Double-check the course direction (023°T) when advancing or retiring LOPs so you don’t move them in the wrong direction along the track. • Compare your final plotted position to the 1900 DR: the change in latitude and longitude from the DR should be small and consistent with your LOP intersection—verify which choice reflects that size and direction of shift.