I hate the parallel rules because they are hard to use with the chart
spread on a pitching cabin floor. Instead I use my hand bearing
compass mounted to aplastic square I can align with north and
perpendicular to the edge of the chart. I have a protractor mounted
to it so I can rotate it about the compass axis. Works for me.
Around here, in most cases, i can ignore the difference between
magnetic north and true north.
The Portland Plotter has a scale that permits instant conversion for
variation. We have 19 degrees east in the Gulf Islands.
Useful gadgets
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