A handy guide to making sense of a nautical chart Whether they are paper or electronic, charts are the most fundamental navigational tool. Making the best use of them requires a great understanding of symbols and abbreviations, as well as an awareness of the limits of accuracy in positions and soundings. Understanding a Nautical Chart not only helps you to read a chart, it allows you to understand that information and use it to navigate safely. Learning the abbreviations and symbols are critical to anybody using a chart and before you can use one, you must know them or at have easy access to the definitions, all of which are included in a full copy of the key to UKHO charts (Chart 5011). The chart information included is presented in the following About the Paul Boissier has spent much of his professional life at sea and was a senior admiral in the Royal Navy. He is also a very experienced yachtsman and has cruised extensively. These perspectives make him the ideal author this guide. Paul is now the chief executive of the RNLI (Royal National Lifeboat Institution), the charity that saves lives at sea and operates over 340 lifeboats around the UK and the Republic of Ireland.