Moving Current Vector

Moving Current Vector
Posted 2022, Aug 23 17:27
In the animations for this module, plotting and then "moving" the current vector is shown as a method of accounting for direction and rate (set and drift). I understand the method and it is informative. However, I'm scratching my head over how to move the vector on paper charts using the chart plotting tools (Breton plotter and dividers) provided for the course. How does one do this?
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Reply 2022, Aug 23 17:51
Place the current vector at the starting position of the boat. Use length of 1 hour e.g. 6 knots in 1 hour is 6 nm. Use angle as given knowing that current flows "to" the angle given. Make sure you follow exactly how to place the vector as shown in the examples.
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Reply 2022, Aug 23 19:27
Thanks Grant. That's how I normally plot the current vector, at the starting position of the boat. However, in the animations the current vector is shown initially plotted at the compass rose or at arbitrary location and then is moved (in the animation) to fit between the COG vector and the scribed 1 hr distance arc. The animation makes this look easy. I haven't figured out how to do that easily on a paper chart.
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Reply 2022, Aug 23 19:36
https://sailing-blog.nauticed.org/how-to-use-a-breton-portland-plotter/
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Reply 2022, Aug 23 19:48
Thanks, got that. My question was answered in the next page of the module (3/10). To "move" (fit) the current vector between the scribed distance arc and COG vector, I set my dividers to the current vector distance and place them on the edge of the Breton plotter. I slide the Breton plotter around until the points of the dividers fit between the arc and the COG line and, voila, I have "moved" the current vector like in the animations. That said, I prefer plotting the current vector at the starting position of the boat, per your original reply. Thanks for the assistance.
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Reply 2023, Jan 28 21:05
Hi, supposedly I'm a bit slow when it comes to learning coastal navigation. So, this may be a simple question but to get the current vector length of 6nm, do I use the dividers along the vertical latitude scale on the chart sides to get 6nm and then transfer it to the correct position and angle? Thanks for any help
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