The Portland (sometimes referred to as a Breton) plotter has revolutionised the way modern sailors navigate. It is an essential bit of kit to help you plot accurate courses and positions quickly. Precision moulded using water clear high impact acrylic material. A comprehensive instruction leaflet is included. A day glow green directional arrow prevents accidental reciprocal bearings and the edges are graduated for tide and boat speed. Is also ideal for constructing instant tidal vectors using the Tidal 2000 system. The base has a fixed grid so the course plotter can be used to plot easily latitudes/longitudes from a Decca or GPS system Also comes in handy at evening classes for practicing chartwork!