Sure Davy thats fine.
Could you let me know on this pic which turn was causing the error.
Each circle is a turn zone.
The boat aims for the centre of the circle.
The boat achieves its waypiont and starts to aim for the next when the centre of the boat first enters the circle.
The 50m circle = presicion turn - therefore starts next waypoint 50m from the centre.
The 100m circles = nonprecision wapoint, so boat looks for next waypoint 100m away from centre.