Wow. I was beginning to doubt my memory---I've never met anyone else who's even heard of a Sportyak, to say nothing of a sailing Sportyak. I learned to sail in a sailing Sportyak back in the late '60's. RobVG, the configuration is called a Cat-rigged Spritsail; it's basically the same configuration as the Skerry I'm building (a kit from Chesapeake Light Craft in Anapolis; another very cool little sailer).
My father improved the sailkit that came with the Yak. I don't recally exactly how the wood members connected at the gunn'ls; I think it was at the oarlocks, but the configuration was two pieces of wood that met at a 90 degree angle above the hole in the forward seat, and the mast passed through a matching hole at that point. Where the two pieces passed out to the gunn'ls and attached, they formed attachment points for larboards: they looked essentially like the lower part of an oar, and were free to rotate down into the water to act as keels, or to rotate back up out of the water if you ran the boat into the shallows.
I recall that the original sailkit was poplar wood; it was pretty cheap and warped pretty easily. My father, being quite the handyman, took dimensions off the existing angled parts, and made new ones out of oak (he'd already made a center seat out of oak so that you could row from amidships instead of from the bow (too long to reach comfortably, especially for a kid of 7 or 8 yrs, as I was at the time) or the stern (what's the sense in rowing backwards all the time???). I don't recall that the Yak was very fast, but it WAS fun. It also set the love of sailing deep---in addition to the Skerry I'm building, I'm the proud owner of a '71 C&C Redwing 35' and I'm looking for a buyer for my '77 Catalina 27' (if I find a good home for her, I'll just about give her away. I can't do justice to maintaining three boats; she deserves one on one attention from someone). And as much as I love the challenge of a larger craft, I still love sailing in the smaller boats, as well.
Thanks for refreshing a great memory...I've almost stopped mentioning it to otehr sailors, because they look at me with a blank stare as if to say, "What the heck is a Sportyak??" (I have resisted, so far, pointing out that 'pram' is an utterly ridiculous name for a sailboat as well...but moral superiority will only get you so far).
Hope to see y'all out there on the water...