Linex Deluxe 9 Inch Protractor Triangle SEMAR - Regional British Admiralty Nautical Chart 1831:

British Admiralty Nautical Chart 1831: Arquipelago da Madeira is a standard nautical chart

4) Dredging or making way with an obstruction on one side – Two green lights or two diamonds in a vertical line to indicate the side safe to pass

this little companion stands up to frequent use and serves as a great aide-memoire that will fit into your pocket or kit bag

The simple cartography defines rivers

UPC Code: 721002911087

Linex Deluxe 9 Inch Protractor Triangle SEMAR - Regional British Admiralty Nautical Chart 1831:Most protractor triangles are 8 inches on the side. These have an extra inch. Since the triangle is larger, the printing is also larger and is in red and black, thus making the numbers easier to discern.