USCG Exam PracticeThree-bearing fix and cocked-hat triangle
A navigator takes a bearing of 270°T to a lighthouse and notes the time. After running a steady course and speed for a measured distance, a second bearing of 315°T is taken to the same lighthouse. The first LOP is then advanced along the DR track by the distance run and crossed with the second bearing. This technique produces a:
- A. Three-bearing fix with a cocked hat
- B. Danger bearing line labelled NMT or NLT
- ✓ Running fix, less reliable than a simultaneous two-object fixCorrect
- D. Fix of equivalent accuracy to a simultaneous two-object fix
Why C is correct
Bowditch Ch. 7 §708 describes exactly this procedure — advancing the first LOP along the DR track and intersecting it with the second bearing — as a running fix. Section §708 explicitly states it is less reliable than a simultaneous two-object fix because it assumes course and speed were held exactly between observations.