From your 1752 position, you steer 313° pgc at 9 knots. At 1805, you obtain the following visual bearings:
Old Pt. Comfort Light - 238° pgc. Chesapeake Bay Tunnel North Light - 136° pgc.
What are the latitude and longitude of your 1805 position?
• Running fix using a DR (dead reckoning) position and later bearings • Converting pgc (per gyrocompass) bearings to true before plotting • Using the vessel’s track and speed from 1752 to 1805 to find the DR position
• How far did you actually travel between 1752 and 1805 at 9 knots, and along what true course? Plot that from your 1752 position first. • After you plot your DR position at 1805, how do the two visual bearings help you shift that DR to a more accurate running fix? • When you extend each bearing from the correct aid to navigation, where should the lines intersect relative to your DR position, and what does that tell you about the correct latitude and longitude?
• Be sure you use the correct time difference between 1752 and 1805 when computing distance run. • Confirm any gyro-to-true correction (gyro error / variation / deviation) that should be applied before plotting bearings and course. • After plotting, carefully read off latitude on the meridian and longitude on the parallel that pass through your running-fix intersection point.
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