Inserting and deleting a leading line on an ADMIRALTY Standard Nautical Chart

To insert a new leading line, first, reference the NM position on the chart using the grid box. Then, align the tracing precisely using the latitude and longitude guides from the tracing and the chart.

With a 7H pencil, mark three points: the end of the leading line, the point where it transitions from a firm to a pecked line, and the end of the pecked line.

Remove the tracing and use a 2B pencil and a ruler to draw a straight guideline connecting the marked points. Re-lay the tracing to verify the guide line's position and length before proceeding.

Using a magenta 0.18 pen and a ruler, draw a firm line between the first and middle marked points and a pecked line between the middle and last points, as shown on the tracing. Ensure not to draw over existing chart information, then write in the legend for the new leading line.

Re-lay the tracing to identify the existing leading line to be deleted. Delete it by adding diagonal double strike-throughs to the line and its legend. Afterward, erase all pencil markings.

Finally, lay the tracing over the chart again to confirm the new leading line's correct position and that the correct existing line has been deleted. Once all updates are applied, add the NM update number to the chart's Notices to Mariners section in the bottom left corner.