Boatbuilding Blog

December 8, 2010

Using an iPad as the Primary Navigation Instrument

Filed under: Building - Electric & Plumbing, Hardware — tomlarkin @ 10:56 am

I’m planning on using an iPad as my primary navigation tool instead of buying a standard chart plotter. To start out, all I need is a $700-$800 GPS-enabled iPad and the $50 iNavX software. I don’t need to buy the cell plan because the GPS works without it.  For that price I could buy an entry-level plotter like the Garmin GPSMAP 546 or the Standard Horizon CP300i, both with substantially smaller screens than the iPad and without the advantages listed below. 

I don’t like Apple’s ‘closed garden’ business model, but there’s no other tablet on the market yet with anything close to the usability of this setup, and laptop computers are a very bad fit for this. I’ve been using OpenCPN on a netbook for navigating, but the screen is too small, the keyboard is in the way, and trying to use a trackpad in a moving boat, especially in the dark, is really difficult.

There are a number of navigation applications for the iPad, but iNavX seems to have more features than the others. Here’s a short video on setting waypoints and creating a route using iNavX. The US NOAA charts are free with the iNavX purchase, and charts from X-Traverse  for much of the rest of the world look reasonably priced.

I found about 20 ways to mount the iPad, but this one looks best so far. The rubber balls should soak up some of the vibration, and it’s easy to adjust, rotate, and remove the iPad. I’ll probably get two sets, one for the dash and another for watching videos below.




  • Wireless – pick it up and use it anywhere onboard
  • Take it home to set up routes and plan trips
  • Huge screen – for the price, the screen is 2 to 4 times the usable size of comparably-priced Chart Plotters
  • Multi-use – surf the web, play music, send emails, watch videos
  • Active development of navigation apps for iPad
  • Easy export of tracks to online maps
  • Switch from portrait to landscape instantly


  • Screen not as visible in direct sunlight as some displays, should be OK in the pilothouse
  • Not waterproof without adding a cover
  • No radar overlay for it (yet)

Hardware & Software:

  • iPad with GPS and 3G, 64 GB: no need to subscribe to the cell plan – the GPS works without it, and the charts are store locally ($830)
  • iNavX software: displays charts and shows current location. Shows data received via WiFi ($50)
  • iMux WiFi NMEA multiplexer: combined information from NMEA devices and transmits via WiFi ($179)
  • iAIS ANT200 Receiver: dual channel Automatic Identification System (AIS) receiver ($299)
  • NMEA-Enabled Depth Sounder with display: example
  • Through-hull transducer for speed and water temperature
  • GPS antenna: external antenna for the AIS receiver and VHF radio (for emergency broadcast)
  • iPad accessories: there are many add-ons for the iPod – chargers, keyboards, speakers, etc.

Everything in the drawing below is optional, except for the iPad itself. I can add parts as necessary.




Analog-style instruments:

AIS overlay on chart:

Track exported to Google Maps: