Navigational charts are produced by the Hydrographic authorities of a country. In our case the authority is the SA Navy Hydrographic Office. The headquarters of the hydrographer is situated at Silvermine in Cape Town.

The charts are compiled and printed according to international standards and conventions and are therefore usable by any seafaring nation in the world. The Hydrographer not only produces navigational charts but also other charts and publications used for navigational purposes in our waters. One of these is a publication with the SA Reference number SAN HO-6 and International reference number INT 1. It is entitled “SYMBOLS AND ABBREVIATIONS USED ON SOUTH AFRICAN CHARTS . This publication lists all the type of information, abbreviations and symbols used on a SA nautical navigation chart. It is an essential publication for the navigator and it is just as essential that the navigator has an intimate knowledge of its contents. Whilst it would be an impossibility to memorise the entire contents, the navigator must be fully acquainted with and recognise the symbols and definitions he is likely to come across on the average chart.

The navigator should be able to:

1. Identify a chart by the chart number and title.
2. Know the basic construction of a chart and the information it contains, ie
   • the scale.
   • the units of measurement of depths, heights, the reference datum for each, explanatory notes, when it was published, what corrections have been made and when, the linear scale, cautionary notes, reference to other charts and nautical publications etc.
   • commonly used abbreviations.
   • understand the compass rose and its construction, what variation applies.
   • identify and recognise buoys, lights, radio beacons, navigational aids, depths/soundings, nature of the sea bed, bottom and land contours, tidal streams, traffic lanes and separation zone, coastal features, chart correction information.