EM-5 at the Cowes-Torquay-Cowes Powerboat races
The answer was, very well (as I'm coming to expect). I stuck with SAF mode and single point focus and shot the bulk of the action hand-held, where the light weight of this system was a real benefit.
With few exceptions the system focused fats and accurately even though a fair bit of it was shooting "contra jour". It was able to isolate action at the start even though this was several miles away into the bay (but at this distance the atmospheric distortion and heat haze became very apparent)
A very satisifying morning's work, my confidence in this system continues to grow (but I can't wait for a professional quality 70-200 f2.8 equivalent lens to be released, it would be ideal for this type of work)
I have created a new album in which I will put some images of the action