We all rely on charts to navigate at sea - but are we missing essential information?A mass of data is included on each chart and deciphering the many symbols and abbreviations can be complicated.The accuracy of some charted depths can be trusted entirely while others should be treated with caution. This book will tell you where to find and how to understand this vital knowledge.This updated second edition explains how charts are compiled before guiding you through the elements that make up these vital navigational tools.Improve your understanding of charts and you will navigate with increased safety and confidence.Understanding a Nautical Chart offers superb value as, in addition to a wealth of practical advice, there is a key to all the recently updated chart symbols and abbreviations from Symbols and Abbreviations Used on Admiralty Charts (5011).It includes information on electronic charts, explains how to update a chart and how to establish the accuracy of each chart. It is ideal for professional mariners and leisure sailors.