Alert!
First post on SW, I found this thread (and Uncle J ' s fin primer) in researching a recommendation from an acquaintance who has steered me right in the past.
I am 6' (one fathom) x 170#, currently riding a 9'2" poly Walden Magic with the 2 + 1 setup - I believe a 6' center with some toe-in to the side bites.
Primarily paddling hard into glorious New Hampshire beach break, most often in knee to waist high wind swell, I rarely make the two hour drive for less than an 8s period, and Sunday morning it was gorgeous 2-3' glass at 8 seconds. I caught more than I missed, but with the rocker of the Magic slowing me some (compared to the 10' flat logs so common in these parts) I am open to any advantage in paddling speed.
(Also conscious of the need to paddle smarter, rather than exclusively harder, experimenting with the 'cork' takeoff and will be reminding myself to start with a few slower strokes so as not to waste my puff, per Uncle J ' s advice elsewhere)
At any rate, one relatively outspoken and friendly chap we'll call Francois (as that appears to be his actual moniker), whom I've often observed making the most of all conditions, selecting waves with alacrity and styling them in with apparent ease, frankly offered, "you should try an FCS Fat Boy as a single fin on that board. I only ride the 2-and-1 when I'm out in California."
I didn't get a chance to interrogate his rationale further, at the moment, but the more I think and read on the question, the more psyched I am to try the single larger fin: and the fat boy seems to be a fine specimen.
I presume the California comparison refers to the typically more powerful and probably larger surf on the left coast. F, at about 5'6" and maybe 160 was riding what looked like a 7'6" Mega Magic with the Fat Boy skeg, and I presume this is the same rig with he goes 2+1, out west (presumably in larger surf).
Also, when Wingnut was out here last summer, I recall he derisively referred to the 2 + 1 as 'cock-and-balls,' as in, "no cock and balls for me, I go with a single." Granted, this would be on different boards altogether, and I believe one of his demo quiver in 'Art of the Longboard' had 2+1, but at any rate I am happy to simplify my setup and press any advantage.
At this point I am very much working on the basics: I'm catching waves and often getting turned down the line, sometimes staying nicely ahead of the curl but just starting to sometimes feel that it's anything to do with trimming or otherwise on my part: increasing my awareness of where I am in relation to the whole wave, and where I'd like to be. I may employ my 12 year old as a videographer, to really find out what's what
My hope is that losing the side bites will reduce drag and allow the foil to provide some extra drive (?) to get me back out to the shoulder when a closeout has souped up the works. It may well be that I am dropping too low, attempting a bottom turn on diminutive humps when I should perhaps be paddling at more of an angle and trying to stay higher across the face.
I have had the board kicked out from under me by a closeout as I was headed for the shoulder, and I hope this deeper keel might let me stay in trim a little longer in such a situation.
All that said, an 8" Fat Boy should ship my way tomorrow, and I will report back any findings, when the next significant swell hits northern New England.