Marine Navigation

How to Navigate the Oceans and Waterways

At its simplest, marine navigation is the art and science of finding your way on the water. It has been used by sailors for centuries to get from point A on the vast globe of the world's oceans and waterways, to point B. Historically, sailors navigated by the stars and constellations. Learning to navigate today includes knowing how to read a nautical chart, knowing the various Aids to Navigation, plotting a course on a nautical chart, following a plotted course and learning to obtain a fix on a nautical chart using marine electronics.

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How to Read a Nautical Chart

Two plotted courses using a parallel ruler and a set of dividers.
Two plotted courses using a parallel ruler and a set of dividers. Photo copyright Ericka Watson

A nautical chart is a “road map” to the oceans and waterways where you take your boat.  It holds the key to a vast amount of information that you need to steer a course to and from destinations in a safe manner.  Without a nautical chart and knowing the various symbols and information, you may as well be driving blind.  A nautical chart shows land, water and its depth, danger areas, landmarks, buoys, lights and other aids to navigation.   It has a compass rose to give you a true bearing in which to steer your boat, a distance scale, and a latitude and longitude scale so that you can you find your location.  With a nautical chart and a few other tools, you can pilot your vessel anywhere in the world that you want to go.​

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Learning and Understanding Aids to Navigation

Worldwide, there are nautical “road signs” that every boater should know and follow such as buoys, lights, and other aids to navigation that assist mariners in determining a vessel’s position and course and that warn of danger.  Each year, thousands of dollars of property damage and personal injury occurs because boaters ignore the crucial skill of learning to navigate.  Just as a stop sign exists to govern traffic and keep motorists safe, aids to navigation also govern boat traffic with the purpose of boats avoiding collisions with other boats or with dangerous shoals, sand bars or underwater obstructions.

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Plotting a Course

Two plotted courses using a parallel ruler and a set of dividers. Photo &Copy Ericka Watson

By becoming familiar with a nautical chart of the area you intend to boat in, you can then plot a course on the chart using the information it provides to help you steer your vessel in “good” water - or water that is deep enough - and around dangerous obstructions. Plotting a course is as simple as drawing lines on the chart in safe areas from point to point, and using the compass rose to obtain the heading you should steer to stay on course. It also includes computing time, speed and distance of each course leg to use while following the course in your boat.

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Following a Plotted Course

A nautical compass with rotating disk
By Kwj2772 (Own work) [ CC BY-SA 3.0 or CC BY-SA 2.0 kr], via Wikimedia Commons

Using the information you plotted on the nautical chart, following the course is simply a matter of using the boat’s compass to steer the heading you calculated from the chart. However, to ensure that you maintain the course, you periodically will need to obtain a fix, or find out where you are according to the coordinates on the chart. You can use the dead reckoning method of calculating your time and speed, or by using electronics such as the GPS and RADAR.

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Making Course Corrections

Skipper at the helm of a sailing boat
deimagine / Getty Images

In spite of your best planning on land, the forces of nature all conspire to throw you off course. Wind, tides, and currents can pull your vessel of its intended track, which over time can lead to danger. This is known as set and drift. Learning to make corrections while your boat is moving is one way to be sure that you remain where you want to be and out of harm’s way.

To be sure, learning to navigate can be challenging. It can seem like there is a lot to learn, but with diligence and practice, mastering the art of navigation is possible and infinitely rewarding.