I believe I noticed somewhere on Nick's site that he has a retractable skeg on his Petrel. You may want to ask him what he used.

~Bob

: Hi Clayton,
: Your obsessed alright,demonstrated by your production output, and,
: possibly, a diminished,kindred spirit...My solution to the
: locked on course and loving it Baidarka Firestar I regularly
: paddle is to build ,as I find myself currently doing,a
: Petrel...Simply to get into learning the skills required to
: manage, what I guess will be, a squirrel of a boat.Now,um,what
: [retractable] skeg design shall I adopt to tame it with?
: cheers,from Paul.NZ