Charts, waypoints, and sonar — the essentials of navigating safely and confidently on the water.
On the water there are no lanes, signs, or landmarks to follow — just open space, hidden hazards, and the need to know exactly where you are. Marine GPS gives boaters that certainty, plotting your position on nautical charts and guiding you safely between points. This guide covers the basics of marine navigation so you can choose a unit that fits your boat and the way you spend time on the water.
A marine GPS, often called a chartplotter, shows your boat's position on an electronic nautical chart. Unlike a road map, a chart displays water depths, buoys and markers, shorelines, restricted areas, and hazards. The plotter lets you see where you are relative to these features, set a course, and track your progress — the marine equivalent of turn-by-turn navigation.
Nautical charts are what make a marine GPS useful. They come preloaded or as add-on cards and vary by region and detail level. Good charts show depth contours, navigational aids, and coastal features. Just as road maps need updating, charts change as waterways and markers do, so keeping them current matters for safety.
These tools let you plan a trip, follow it precisely, and return the same way — invaluable when weather or darkness reduces visibility.
Many marine units combine GPS with sonar, creating a fishfinder-chartplotter combo. Sonar reveals water depth, bottom structure, and fish below the boat, while the GPS marks productive spots as waypoints. For anglers this pairing is especially valuable, turning the display into both a navigator and a fishing tool.
| Consideration | What to think about |
|---|---|
| Screen size | Bigger helps on open water; balance with helm space |
| Chart coverage | Match to the waters you boat in |
| Sonar | Add a fishfinder combo if you fish |
| Waterproof rating | Essential for exposure to spray and rain |
| Mounting | Flush or bracket mount at the helm |
A marine GPS is a powerful aid, but good seamanship means carrying backups. Keep paper charts and a compass aboard, know your local rules and markers, and treat the plotter as one tool among several. Waterproofing and a bright, readable screen matter because conditions at sea change quickly.
A marine GPS rewards a little practice before you truly need it. Spend time in familiar waters learning how to drop a waypoint, build a simple route, and read the chart's symbols for depth, buoys, and hazards. Set up the display so the most useful information — position, heading, speed, and depth if you have sonar — is visible at a glance from the helm. Learn how your unit warns of shallow water and how to follow a track back to the dock, so that when fog rolls in or light fades, the actions you need are already second nature rather than something to figure out under pressure.
Match the unit to your boating. Weekend anglers on inland lakes have different needs than coastal cruisers. Confirm the chart coverage fits your waters, decide whether you want integrated sonar, and choose a waterproof unit with a screen readable in bright sun. With the right marine GPS, you can explore new waters with confidence.
Quick answers for boaters and anglers.
Chartplotters and marine units for every kind of boating.
Marine GPS turns open water into navigable space, plotting your position on charts and guiding you with waypoints, routes, and tracks. Match chart coverage to your waters, decide on sonar, and always keep backups aboard. Browse our Marine GPS range or read Outdoor Navigation Essentials.