Review of OpenCPN Navigational Software

Powerful Free Laptop Software for Real-Time Chart Navigation

OpenCPN Screen Shot 1
Screen showing route.

OpenCPN is a free chartplotter software program for PCs that offers a wide range of features rivaling those of expensive software packages. With a laptop coupled with a GPS receiver, and using free American charts from NOAA, OpenCPN allows real-time navigation with standard chartplotter functions. OpenCPN was built by sailors and is a gift of surprising value to boaters preferring to use a laptop for navigation rather than an expensive dedicated chartplotter.

If you are unfamiliar with what chartplotters are and what they do, it is helpful to read this introductory article first.

Version reviewed: 2.4.620 running on an inexpensive netbook with Atom processor

Key Features of OpenCPN

  • Use easily installed free NOAA charts for US coasts and some other international electronic charts
  • Connect your laptop to a GPS receiver such as the Dual XGPS150 Bluetooth GPS Receiver to see the boat in real time on the chart and use all plotter functions
  • Adjustable ship-tracking options for display
  • Easily plot waypoints and make routes (photo 1 above)
  • Automatic chart quilting (joining separate charts of the same scale)
  • Zoom in an out, scroll and pan, or scale in and out of different charts
  • Shows tide levels and currents (built-in and offline) on demand (photo 2 above)
  • Instant man-overboard marker with automatic return course, distance, etc.
  • Change color/brightness schemes for daylight/nighttime conditions
  • Detailed and well-written (offline) instruction manual and help screens included
  • Full route management
  • Available for Windows, Mac, and Linux operating systems - Android app coming

Advanced Features of OpenCPN

  • Mouse and keyboard functions make features easy to use with toolbar buttons or hot keys
  • Works with raster charts or ENC vector charts from NOAA
  • North-up, course-up, and look-ahead chart display modes
  • Set audible anchor alarms in case the anchor pulls or the boat swings too close to shore or an obstruction
  • Import and export waypoints, routes, and other information from other programs and devices
  • When connected to an AIS receiver, plots positions of large ships required to emit Automatic Identification System signals - with collision alerts and alarms
  • Includes a measuring function to quickly determine distances between points without having to build a route
  • Status bar makes it easy to switch among different scale charts for the area
  • Plug-in to display GRIB wind data overlaid on chart
  • Output to autopilot

Some of these features are not available in software packages costing hundreds of dollars - but are included in this free product. You can tell OpenCPN was developed - and is continually improved - by sailors.

The Downside

In my testing everything worked extremely well, even running on a low-power netbook. Chartplotter functions were excellent, and the software proved very responsive with the boat in motion. Given that this is a free program and shows an incredible effort of a dedicated team, I hesitate to even mention a couple little things that could be improved (and perhaps will be in the future):

  • The bar at the bottom of the screen showing long/lat, SOG/COG, and other information is very tiny and difficult to read on a smaller laptop screen or on a moving boat - and difficult to read black type against dark gray.
  • I ran into one bug that may have occurred partially as a result of my own fiddling around with the controls. At one point my chart display got, well, a bit goofy - perhaps when I tried to use the look-ahead mode (showing what the chart looked like ahead of my movement) without having auto-follow activated (an illogical thing to do, it would seem).
  • While the program is mostly intuitive to use, some advanced functions are more complicated and require consulting the manual step by step. For example, I love the anchor alarm feature (see photo 3 above), but several steps must be performed precisely to make it work - requiring consulting the manual back and forth with the chart screen. First drop a mark, then go to mark properties and change the mark icon to an anchor and the name to a numeral (in meters) for the diameter of the anchor circle, click OK, right click again and click Set Anchor Watch. There must be an easier way? And be sure to delete that anchor mark later on, or next time you set an anchor watch somewhere else, you may start getting alarm bells because you're away from that earlier watch zone!


While many navigation apps are now available for smart phones and other devices, they lack many of the features available in a larger software package - making a laptop better for many navigation purposes.

OpenCPN has many more features than Sea Clear II, the other free PC navigation program, and OpenCPN is much easier to use. Sea Clear provided a valuable free program for many years, but now there's really no comparison.

OpenCPN also compares very well with several commercial packages that cost hundreds. If expense is not a factor, you might prefer a different program with features like integrated ActiveCaptain Interactive Cruising Guidebook or advanced weather information or radar overlay.

But if you're looking for very solid chartplotter software with terrific features and that is easy to use, look no further than OpenCPN. That it is free is a bonus. Consider its only downside its unwieldy name!

For more screenshots and to download, visit the OpenCPN site.

For a laptop navigation and plotting program with more powerful features, do a test drive of the inexpensive Polar Navy program.

Navigatrix is a free full suite of software programs running under Linux that can be run on a PC or Mac laptop, including chartplotter, weather data, and much, much more.