When boating, the ability to read a nautical chart allows you to orient yourself on the open waters. This is a prerequisite for all boat operators to avoid being stranded. To help you understand nautical marine charts, the National Boating Safety School explains what you need to know.
A nautical chart is a representation of the ocean floor in the form of a paper map. This chart is published by the Canadian Hydrographic Service to assist captains in their navigation and to show the types of seabed, water bodies and oceans.
Being able to read a nautical chart is important to guide you on the water, but above all to identify hazardous areas to avoid running aground or causing an accident.
You’ll find various symbols, abbreviations and terms on your chart and may find yourself in tricky situations if you’re not familiar with them. Even if you have all the required boating safety equipment on board, it is still best to avoid having to use it.
Another point is that a nautical chart, like a fishing chart, is drawn following the contour lines and nature of the seabed. The nomenclature is used internationally and is adapted according to the country.
The colours on a nautical chart indicate the depths and types of seabed. Here is what each colour represents:
The numbers on a marine chart are also important for navigation. They provide more information about the depth of the waterbed and give a more specific indication of elevation. They can also indicate the presence of objects or rocks that are not always visible depending on tides and weather conditions.
|REP||Reported, but not surveyed|
Often near the shore, these markers indicate the characteristics of the waterbed. This information is important for anchoring a boat.
These indicate the type of bed:
|Wd||Weed (including kelp)|
|Sh||Shells (skeletal remains)|
|Co||Coral and Coralline algae|
When two letters are separated by a slash, this indicates that you are dealing with a mixed seabed. The first letter will always indicate the majority type.
They will indicate the quality of the seabed:
Depending on the waters you navigate, you may find letters that indicate other dangers:
The first step in reading your nautical chart is to set up your navigation plan. Once you’re on the water, use your magnetic compass and navigation radar to guide you. Your chart will keep you informed about the type of seabed you’re navigating and where to anchor.
Marine nautical charts also come in handy when weather conditions change and high winds arrive without warning. You’ll have a better understanding of the seabed and where to find safety and refuge as soon as possible.
A nautical chart is a very useful tool for recreational and commercial navigation. All over the world, boat captains use them to find their way around the water and identify the seabed.
As a key part of your boating license, the National Boating Safety School provides an online boating safety course to help you learn everything you need to know before taking the official online boating exam. Register now to get your license and start navigating on the water.