Nautical charts are graphic representations of areas of the seas and oceans, along with adjacent stretches of coastline. They are based on what are known as hydrographic surveys and are used as navigational tools by sailors. Further information about hydrographic surveys can be found in the PDF attachment. As a qualified naval engineer and member of the board of directors for Russia’s largest shipping company, Sovcomflot, Victor Olerskiy has a lifelong interest in all matters connected with the sea and the global marine industry. Victor Olerskiy served in the Russian Federation as the head of the Federal Agency for Maritime and River Transport between 2016 and 2018. Nautical charts are an essential part of navigating marine waters, with today’s sailors using a combination of paper and electronic charts along with other navigational tools. Nautical charts are annotated with numbers that give depth measurements of the waters.
Nautical Chart Features
A nautical chart may show a number of features depending on the scale of the chart. Commonly, nautical charts will show a topographic map of the waters, indicating the height of any land and the depths of the water in different areas. Navigational hazards at sea are shown, along with human-made structures such as bridges, harbours and buildings. Information about currents and tides is often provided, along with localised details of the magnetic field of the earth. Details of the surrounding coastline and natural features found on the seabed are indicated, along with the location and type of various aids to navigation, both natural and human-made.
Paper and Electronic Charts
There are two main types of nautical chart in use today: paper charts and electronic charts. Recent technologies have also ensured that sailors can print the latest paper charts on-demand, featuring cartographic data that has been downloaded as recently as the previous night. Each daily download adds in new information such as local notices and other critical data, which ensures the chart being used is as current as possible. Computerised navigational charts use databases and software to provide all the relevant information for navigation. Paper charts are printed in a variety of scales on large sheets of paper. Typically, mariners will carry a selection of paper charts to be able to access the information they need in sufficient detail for the particular area they intend to navigate. While use of technology is becoming more widespread, many mariners will also carry paper charts to act as a backup in the event of the electronic system failing. In many countries, it is a legal requirement for vessels to carry nautical charts.
Chart Corrections and Limitations
Historically, a sounding line was used to measure the depths of waters and check for possible hazards. Today, marine cartographers use echo sounding. Find out more about echo sounding in the short video attachment to this post. As the nature of oceans and waterways are changeable, it is vital for mariners to never use old or outdated charts. Human-made aids to navigation may also be changed, making it even more important to be up to date. Every nautical chart producer in the world uses systems to ensure that sailors can be informed of any changes that may affect the data provided on the chart, be that paper or electronic. Despite the care taken over producing nautical charts, it is always possible that there may be unforeseen hazards in the water, so mariners are always advised to assume that any chart they use might be incomplete.