The turret location is a key design issue. With the turret at greater than 75% of overall hull length from the stern, the vessel weather-vanes free.
At around 65% (3 of 4 FPSOs in the market), thrusters are required to maintain and control heading. The controlled heading FPSOs have the advantage of being able to lock the turret and thereby reduce bearing and swivel wear. However, this places a demand on the thrusters (which are safety critical) and the crew to manage turret repositioning.
Any additional inputs from the experts?