Dan has all the skills - the spock 540s, 1 handed back loops and goitres out the back show that nicely!
From watching ALOT of video of sailors on single vs multi fin boards (i am going through tons of raw footage from Hawaii - april 2010) - as well as trying a few myself - this is what i am noticing:
airs not out onto the flats / crashes- i have noticed that multi fin boards tend to keep you with the lip as you try and pop an aerial - often leading to a crash as you land with the lip. This is from watching alot of raw video of Bouj , Kp (riding singles and quads back to back)
After you hit the lip - Singles get you out in front of the wave WAY more - as the deeper fin seems to grab more thrust out of the lip.
However singles - in general - are a bit stiffer requiring more leg force from the rider to force a turn. Or a more out the front turn into a vertical attack. Singles seem to throw about double the amount of spray out the back of the wave
multi fins tend to have a much looser open faced turn with less of that turning force required to be supplied by the rider. They mid face turn much easier and make mushy waves look powerful. But they do have that problem of sticking in the lip..
In short - single = projection, big spray multi fin = looseness
Ideally you would have a single and a multi fin board and pull them out when conditions suit either.
exceptions: Jaeger Stone on what i would call a widow maker set up - which seems to ride very close to single fin style (good lip projector) but with some of the looseness of a twin /quad mixed in. And i have seen simon peters projecting big time at margs on a quad set up.
