At 0445 you take the following lines bearings:
Montauk Point Light 292°pgc Block Island Southeast Point Light 024°pgc
What was the current encountered since your 0400 fix?
• Set up a DR (dead reckoning) track from your 0400 fix using your ordered course and speed to 0445 • Plot the two simultaneous position lines (LOPs) from Montauk Point Light and Block Island Southeast Point Light at 0445 to obtain an observed fix • Determine the current vector as the difference between your DR position and your observed 0445 fix (set = direction, drift = speed)
• From your 0400 fix, where would your DR say you should be at 0445 with no current? Plot that first. • Where does the intersection of the 0445 bearings place your actual position relative to the DR position (direction from DR to fix and distance between them)? • Convert the distance between DR and fix over the 45-minute interval into knots, and express the direction as a true current set (toward which direction the current is flowing).
• Be sure your DR track is drawn correctly from 0400 to 0445 using the correct course and speed and elapsed time (45 minutes). • Confirm you are measuring the current vector from the DR position at 0445 to the observed 0445 fix (not the other way around). • When converting distance to speed, remember 45 minutes is 0.75 hours, and express the result to the nearest 0.1 knot before matching to the choices.
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