USCG Exam PracticeThree-bearing fix and cocked-hat triangle
A vessel takes a bearing of 270°T to a lighthouse and records the time. After running a measured distance on a steady course, a second bearing of 315°T is taken to the same lighthouse. The first LOP is then advanced along the DR track to the time of the second bearing. What type of position does the intersection of the advanced LOP and the second LOP produce?
- A. A three-bearing fix with a cocked hat
- B. A danger bearing line of position
- ✓ A running fix, less reliable than a simultaneous two-object fixCorrect
- D. A confirmed fix, equivalent in accuracy to a simultaneous two-bearing fix
Why C is correct
Bowditch Ch. 7 §702 and §708 define this procedure as a running fix. It is less reliable than a simultaneous fix because it assumes course and speed were held exactly between the two observations.