Not positive, Bill, but I'm gonna jump in here and suggest that they have a nicely ballasted design that utilizes batteries, heavier stores and even water reserves for stabilizing the big dude. I have not seen any evidence that they use something like a retracting set of outriggers, so it would have to be a ballast scenario.

Some years ago, a guy tried to paddle/kite across the Atlantic and his boat had a slender fin keel with a bulb of lead on it for stability.

The overall boat design/build of this project has been kind of on the secretive side of things. There have been some photos of the boat in the shop, but they do not, to my knowledge, show the whole form.

Casting about, I found this interesting discussion on the topic of long range expedition "kayaks" along with some really cool shots of the practice boat used by Peter Bray for his ocean crossing effort.

Do read the postings below the intial blog article for additional interest on the topic.

http://www.kayakquixotica.com/2007/11/15/thats-not-a-kayak/

Perhaps the most interesting element, which connects to your comments, Bill, about moving about on board, are the images that clearly show the stabilizer fin on the port side. My guess is that there are two fins (opposed) and that they are weighted for self-righting in the event of a roll in heavy weather.