Thanx for the heads up; I remember Mr Miller promising to relay a utility socket request but I didn't expect to see it. I will await to hear your debug experiences whether this clever approach works ok. I think you can start by just bungeing the pedal shafts together to form a static daggerboard (preserving kickup). There is a way to bungee your drive in use without restricting pedaling; that way you don't forget to keep the fins straight down when not in action. Maybe consider turbo fins.
I
would consider 2 sails (maybe find used ones) because the old tandem hobie i14 used to seem so underpowered in videos that I think it might lose rudder authority and get turned by waves. My old beloved i12 kayak hated downwind because the boomless sail would taco, but loved upwind when the sheet stretched into a nice airfoil. For fun I used to "sail by the lee" with tight sheet downwind, or you could add a boom-batten which can also help reaches.
Waves can give a yaw problem at least for the solo craft, so try short fetches before passing judgement. OK, I need to find a doctor who will prescribe an Itrek 9 ultralight as a medical device for my frail back. I am a bit skeptical that utility hole is forward enough to avoid weather helm (which even my old i12 had and thus I raked mast forward) but maybe I can balance with a jib
