Speed over ground (SOG)

•Indicates speed over ground as received from the GPS

Velocity Made Good (VMG)

•Indicates current velocity made good, as calculated from speed and course over ground

•The heading used for the calculation is easily entered from the buttons on the case or the remote

Trend arrows

•See the trend in speed or VMG over a few seconds right next the instant numeric display

•Gives an indication of loss or gain after a change is made, or acceleration after a tack

Course Over Ground (COG)

•Indicates course over ground as received from the GPS

Starting line distance

•Indicates the perpendicular distance from the RockBox to an infinite starting line that goes through the two marks

•Dedicated buttons on the case make it easy to press the right button when in position to set the marks

•Easily reset one or both marks at any time

•Plus and minus side of line indicator

•The fast update rate of the GPS inside the RockBox really shines here!

Countdown timer

•Dedicated button on the case makes it easy to set and start the timer

•One minute increments in the time set allows synchronization of the timer even if a 5 minute gun is missed

Knock-lift indicator

•Graphically indicates the difference between a base heading and your current heading

•Allows easy identification of wind shifts while sailing upwind

•Remembering a series of headings to spot wind shifts is not necessary anymore!

•Indicates your current course versus a base course


•Graphically indicates a history of speed or VMG

•Make it easy to see changes in speed or VMG over time, without the need to remember old values

•Spot drop offs in speed to know when a sail or trim change is needed

•After a trim change is made, you can let the boat settle in for a while and see the result

Waypoint Distance:

  • Indicates the distanct from your current position to the current waypoint

Waypoint Bearing:

  • Indicates the bearing to the current waypoint in your choice of two methods
    • True: The course to steer to the waypoint
    • Relative: The bearing to the waypoint relative to your boat's bow

Time to Waypoint:

  • Indicates the time to thee current waypoint, based on your current position and speed

Project a Waypoint:

  • Saves a waypoint at the distance and bearing from your current position that you enter
  • Very useful in a regatta where the R/C boat displays the distance and bearing to the first mark!

Save a Waypoint

  • Saves your current position as a waypoint

Data logging

•Lets you review your performance and path after a race

•Outputs the standard NMEA GPRMC sentence containing:

•Speed over ground

•Course over ground





•Easy to disable by removing the SD card, for classes that ban data logging

Magnetic compass, heel angle, fore/aft trim angle: Available in the pre-release Beta version of the firmware

See the Future Development section for news on additional functions under development