In the upcoming version 3.06.0 of iRegatta, it's been made easier to prepare a race course with waypoints and update it while you go around the course.
When creating a route, you now have 4 new waypoints you can put in your route: Buoy 1, Buoy 2, Buoy 3 and Starting vessel.
So before the race, you prepare a route with the course you are going to race (ex. Buoy 1, Buoy 2, Buoy 3, Buoy 1, Buoy 3, Starting vessel - This would be a "triangle-sausage" type of cause.
When you ping the boat end of the starting line, this position is automatically stored in the "Starting Vessel" waypoint.
You may also know the approx. length of the first upwind, so you can make a new temporare waypoint using the "Bearing & Distance" feature or the "Cross Bearing" (iOS only) feature. When you tap the "Save" button, you'll get some new options in the "Add Waypoint" view that pops up. At the bottom of the view you can chose to store this as Buoy 1, Buoy 2 or Buoy 3.
Once you start racing, you can store the exact positions of the marks as you round them. The course view is a new view that's available when you slide down from the Navigation view. Here you can tap on any of the 3 buttons to mark current position as one of the buoys. So now you have an exact position to use for the next time around. If you've got the time to mark the Buoys before racing, you are even better off...