BH Navigation Portland Plotter

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