Applying an NM block to an ADMIRALTY Standard Nautical Chart

Updates are applied as blocks when the complexity of the update is too great for a textual notice. Tracings are not provided for blocks, but textual NMs will indicate the central position.

Position the block on a flat surface for cutting. Blocks include at least 5 millimeters of coverage within their boundary that contains no new or deleted information.

Using a parallel steel rule and a scalpel, carefully cut out the block, removing the enclosing black border line while staying within the 5-millimeter overlap.

Place the cut block onto the chart to check its fit. Before applying, use a magenta pen to write the NM number within the block area on the chart as a backup in case the block detaches.

Apply adhesive to the block, then carefully place it in position and press firmly. Recheck that the block's position is correct and no information has been missed.

Finally, add the NM update number to the chart's Notices to Mariners section, located in the bottom left corner.