At the back of the boat, we can see one of the two GPS Compass antennas.
This is the new 10 Hz. satellite Compass from nke. It delivers true heading accurately anywhere in the world as well as GPS position and course over ground.
The GPS Compass does not require any calibration, being independent from all magnetic influences on board. This is the best heading data alternative in regions where magnetic compasses are not reliable (south seas)
More information about the GPS Compass here
Photo credits : Barcelona World Race