How Do You Read Coastal Navigation Charts?

Reading Coastal Navigation Charts: A Guide for Sailors

Sailing is an adventurous and exciting activity, but it requires proper preparation and skillful navigation to keep you safe in the waters.

One of the most important tools for navigation is the nautical chart, which is used to determine your location, plan your course, and identify potential hazards while sailing in coastal waters.

In this article, we’ll discuss how to read a nautical chart so you can safely navigate your vessel while sailing in coastal waters.

What Is a Coastal Navigation Chart?

A nautical chart or coastal navigation chart is a map-like representation of a section of the ocean or sea, detailing information such as depths, shoals, currents, tides, and other navigational hazards such as rocks or shoals that can potentially be encountered during sailing trips in that area.

Nautical charts are created by different hydrographic offices around the world and are available in paper form or digitally, they usually cover a specific area from shoreline to shoreline with lots of detail about what lies below the surface of the water between those two points.

Types Of Charts

Nautical charts come in several different types depending on their intended use: paper charts for navigators who prefer traditional methods, electronic charts, and vectorized charts that provide more detailed information about what lies beneath the water’s surface.

Most sailors prefer to use vectorized charts since they provide more accurate information about depths and other potential hazards that can be encountered while sailing in that area, however, electronic charts are becoming increasingly popular due to their ease of use and availability on mobile devices such as smartphones or tablets.

Reading The Scale

The scale at the bottom right corner of the chart indicates how much area it covers and helps you determine distances between points, distances are typically shown in statute miles (nautical miles are also sometimes used).

To calculate distances between two points on a chart, you can use a ruler or dividers to measure out each mile along the path from one point to another – this will give you an approximate distance that you can then convert into statute miles (or nautical miles if needed).

Identifying Direction and Distance

Arrows with numbers indicate direction and distance between points on your chart, these arrows show you which way to go when navigating from one point to another as well as how far apart those two points are (in statute miles).

Additionally, some arrows may have Roman numerals next to them which indicate compass directions (e.g., N for north).

Reading Symbols

Symbols represent buoys, rocks, shoals, sandbars, wrecks, reefs, lighthouses, bridge abutments and other navigational hazards – all of which you should be aware of when sailing in coastal waters so that you can avoid them if necessary.

Knowing what each symbol means will help you identify potential obstacles before they become an issue while sailing so that you can plan your route accordingly or take appropriate action if needed.

Notations On Charts

Most nautical charts also contain notations such as depth contours (in feet), bottom composition (sand vs rock vs coral), soundings (in fathoms), offshore structure type (reef vs pinnacle vs sandbar) and various other information related to navigation – all of which should be taken into consideration when planning your course through coastal waters so that you can safely navigate around any potential hazards identified on your chart before entering them into your GPS system for tracking purposes later on during your voyage.

Interpreting Depths & Soundings

Depth contours help sailors determine how deep the water is at any given point along their course – lines parallel with each other indicate constant depth throughout an area while lines radiating outward from each other indicate increasing depths toward deeper water areas.

Additionally , soundings are often printed on nautical charts , indicating specific depths at precise locations , these soundings should always be taken into consideration when navigating through shoal or shallow waters.

Using a Chart Plotter

A chart plotter is a device used by sailors to accurately track their position using GPS data , display their tracks on electronic nautical charts , and plan routes based off of this data. Chart plotters come with built-in software packages containing detailed information about various navigational hazards so sailors can identify them quickly without having to manually check every chart symbol , they also have built-in alarms which alert sailors when they’re approaching shallow water areas or other navigational hazards.

Tides & Currents

In addition to identifying potential navigational hazards , it’s important for sailors to understand how tides & currents work in an area before setting sail. Tides & currents affect both speed & direction of vessels , so understanding these forces will help sailors make better decisions while navigating through coastal waters.

Tidal range & direction can be found on most nautical charts , along with current strengths & directions at specific times throughout the day , this information should always be taken into consideration when planning routes through coastal waters.


Reading nautical charts is essential for any sailor looking to navigate safely through coastal waters – not only will it help you stay safe by identifying potential obstacles before they become an issue , but it also allows you to plan efficient courses around any obstacles identified.

It’s important for every sailor to familiarise themselves with both paper & digital versions of nautical charts before setting sail , this way , they’ll have all necessary information available at their fingertips no matter where they might find themselves during their voyage.

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