You are steaming on a course of 025°T at...

Question 1 of 31048fy_heal_CREATE_q138_2027

You are steaming on a course of 025°T at 15.5 knots. At 0645 you observe a lighthouse bearing 059°T. At 0655 the same lighthouse bears 075°T. What is your distance off at the second bearing?

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Question 1 of 31048

You are steaming on a course of 025°T at 15.5 knots. At 0645 you observe a lighthouse bearing 059°T. At 0655 the same lighthouse bears 075°T. What is your distance off at the second bearing?

🔍 Key Concepts

• Running fix using two bearings of a fixed object • Conversion of time and speed to distance run using $\text{Distance} = \text{Speed} \times \text{Time}$ • Relative geometry of bearings: how the change in bearing relates to your track line and distance off

💭 Think About

• How far did you travel between 0645 and 0655 at 15.5 knots? Convert the time difference to hours first, then apply the speed-distance-time formula. • On a plotting sheet, if you advance your track line between the two observation times, how do the two bearing lines from the lighthouse intersect that track? What geometric figure is formed? • How does the angle between the two bearings help you relate your run (distance traveled) to your distance off at the second bearing?

✅ Before You Answer

• Be sure you convert 10 minutes into hours correctly before multiplying by 15.5 knots. • Carefully measure or calculate the angle between the two bearings (059°T and 075°T) and relate it to the triangle formed with your track line. • Verify that the final distance off is in nautical miles and is consistent with the distance you ran in 10 minutes (it cannot be unrealistically larger or smaller than the run).