The maximum ebb current at a location 4.3 miles south of Stratford Point will occur at 0413. The predicted current will be 1.0 knot at 075°. What will be your course made good if you steer 082°T at 8 knots?
• Set and drift of current and how they affect your actual path over the ground • Using current triangles (current vectors) to combine ship’s speed through the water with current • Difference between course steered (compass/true) and course made good (over the ground)
• Draw a current triangle: which side represents your ship’s 8-knot speed through the water, and which side represents the 1.0-knot current at 075°? • From your starting point, how does a current setting 075° push your vessel if you are steering 082°T—does it move you more to the left or right of your intended track? • Once the triangle is drawn to scale, which direction (true) does the resultant vector point—slightly higher or lower than 082°T, and by about how many degrees?
• Make sure you are using true directions for both ship’s course and current set. • Confirm that the current speed (1.0 knot) is small compared to your ship’s speed (8 knots), so the course made good will only differ by a few degrees, not a large angle. • Verify that you are measuring the resultant course from the origin to the tip of the combined vector, not just averaging the two directions.
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