Blundell Harling: Portland Course Plotter and Divider kit
13 inch Portland Course Plotter and Divider kit.
A bright blue directional arrow prevents accidental reciprocal bearings and the edges are graduated for tide and boat speed.
The base has a fixed grid so it is easy to plot latitude from your GPS system.
The Portland Course Plotter Kit includes a 7 inch Single Handed Divider.