After departing the New Haven terminals, your 1800 position puts the New Haven Harbor Lighted Whistle Buoy "NH" bearing 130°T at a range of 0.2 mile. From this position you set a course to leave Stratford Shoal Middle Ground Light 1.0 mile off your starboard beam. Your speed is 12.5 knots. At 1845 you determine your position to be LAT 41°05.5'N, LONG 73°03.1'W. What were the set and drift of the current?
• Course made good vs. DR (dead reckoning) track between 1800 and 1845 • How to plot a beam range (1.0 mile off starboard beam) to Stratford Shoal Middle Ground Light • Vector triangle for set (direction) and drift (speed) of current
• From your 1800 position and ordered course/speed, what DR position should you have at 1845 if there were no current? • When you plot your actual 1845 fix and compare it to the DR position, in what direction has the current pushed you, and how far? • Once you know that distance and the elapsed time (in hours), what is the speed of the current, and does current set toward or from the direction you label as set?
• Be sure you convert 45 minutes to 0.75 hour before calculating drift in knots • Verify that set is always expressed as the direction TOWARD which the current is flowing, in true degrees • Double-check that your DR track between 1800 and 1845 uses the correct speed (12.5 knots) and the proper course line from the initial position (leaving Stratford Shoal 1.0 NM off the starboard beam).
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