Portland Navigation Plotter

1. Movable disc enables magnetic variation to be set on the instrument
2. Movable arm is divided into millimetres
3. Captain Fields' protractor markings
4. Comfortably covers the largest Admiralty Chart
5. Pencil guide holes give precision loction
6. Unique design ensures a truly parallel action
7. Special "slip and grip" for ease of use
8. Manufactured from clear acrylic
9. 400mm in length