From your 0939 position, you wish to change course in order to pass 0.3 mile north of Buoy "NCA" (LL#375) in the inbound traffic lane. You estimate the current to be 150°T at 2.0 knots. What course should you steer to make good the desired course? Your speed is still 13.0 knots.
• Set and drift of the current and how they affect your course made good • Using a current triangle / vector triangle with ship’s speed and current to find course to steer • Difference between course to steer and course made good over the ground
• First, imagine (or sketch) the line you want to follow from your 0939 position to a point 0.3 NM north of Buoy NCA. What true track over the ground does that line represent? • Then add the effect of the current: in your vector triangle, which side represents your 13.0‑knot speed through the water, and which side represents the 2.0‑knot current? Which angle in that triangle is the course to steer? • After you find the required course to steer from your plot or vector triangle, compare it to the given options. Is it logical relative to the direction of the current (150°T) and your desired track direction toward the inbound lane and buoy?
• Be sure you are using true directions consistently (not mixing magnetic and true) • Verify that your plotted or calculated course to steer compensates for the current setting you toward or away from the buoy, not along your track • Double‑check that you used the correct speed values: 13.0 knots for the vessel and 2.0 knots for the current when constructing your vector triangle or doing any calculations
No comments yet
Be the first to share your thoughts!