🔍 Key Concepts

• Running fix with multiple celestial LOPs – how to advance earlier LOPs to a common time using course and speed • Relationship between track line / DR position and the final fix – is the fix usually ahead/astern and slightly left/right of DR on that course? • Effect of north/south and east/west intercepts on latitude and longitude – whether each LOP pulls the fix toward or away from the assumed position

💭 Think About

• First, sketch your DR track from 0500 to 0550 and mark DR positions at 0520, 0535, and 0550. How far along track do you move between each observation? • Think about the bodies’ declinations (far south, far north, and south again) relative to your latitude in the southern hemisphere. Should these sights tend to pull your fix slightly north or south of DR? • Look at the four answer choices: which ones are consistent with a vessel steaming 16 knots on 291° T for 50 minutes starting from the given DR? Pay attention to which are significantly north/south and east/west of the 0550 DR.

✅ Before You Answer

• Compute and note the DR position at 0550 on course 291° T at 16.0 knots from 0500 – then compare that with all four choices. • Estimate whether your total track from 0500 to 0550 should result in a greater change of longitude or latitude, given you’re at 28° S on a NW’ly course (291°). • Before choosing, eliminate any options that are clearly too far off the DR track for only 50 minutes of run at 16 knots, either in latitude or longitude.