At 0925, you plot the following: Falkner Island Light bearing 252°T at 1.8 nm If you correct for a current setting 035°T at 0.5 knot, what true course will you steer from the 0925 position to arrive at a position 0.5 mile south of Long Sand Shoal West End Horn Buoy "W"?
• Current correction using set and drift on a course line • Using 1 hour = 60 minutes of arc on the latitude scale to convert speed to distance over time • Difference between track (course made good) and course to steer when a current is acting
• First, ignore the current and think about what true course you would plot from your 0925 position to a point 0.5 nm south of the buoy. How would that course compare in general direction to the answer choices? • Next, consider the set 035°T and drift 0.5 knot over the time you expect to run this leg. Will that current push you to the left or to the right of your desired track? Will it set you more north or more south? • After deciding which way the current pushes you, think: must the course to steer be more toward the current or away from it in order to end up on the desired track?
• Estimate or compute the time it will take to run from your 0925 position to the point near the buoy at your intended speed; you need that time to figure total current effect. • Plot the set vector (035°T) and its distance for that time, then construct the triangle of velocities to see how your heading must differ from your desired track. • Before choosing an answer, check whether your final course to steer should be numerically higher or lower than the no-current course you first plotted; eliminate options that don’t match that logic.
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