Thanks - this is a new boat, so I have a lot to learn, and am still finding the magic settings... I should say that by "rotation fully on" I mean fully pulled on, to decrease it, i.e. MINIMUM rotation - sorry!

Cheshirecatman, it's interesting that you mention pre-bend: The sail was flat to my eyes all over, until the luff collapsed. However, I was using less pre-bend than had been recommended. The boat manufacturer had reco'd spreaders forward and max pre-bend as my default setting, which I thought would de-power me too much. Your comment makes me think that with max pre-bend it would be better for these conditions.

I have previously (Spitfire) set the spreaders and pre-bend in the middle and left it alone, and I am trying to find a setting where I can set and forget on this one too. I guess that with this boat a little more tuning is needed to optimise performance. No bad thing, so long as you know to do it!

It is possible I was luffing the boat - it was "quite windy". I thought about bearing off to de-luff it, but it felt overpowered like that (i.e. sideways).