Custom Navigation Software
We use a custom written set of navigation software that displays the typical 'follow-the-road' course that additionally contains a 'rabbit' that indicates the time when we should be at a certain point on the road.
(The rabbit is the blue flag in front of the boat symbol. If we were 'on-time' the bow of the boat would be exactly at the base of the flag.)
The software takes input from a NEMA-183 serial wire, to calculate GPS position and speed-over-the-bottom, and a contest route file. The boat is displayed at the GPS position and the rabbit is displayed using the route information.
A contest is then simply 'follow-the-rabbit'.