The 10 footer I built is based on the N. Alaska retrieval kayak on David Zimmerly's website:

http://arctickayaks.com/Plans/PlansNorthAlaskaRetrieval.htm

Its not real fast, but its fun and handles easily.

I had to make my own cross section stations from the line drawing - the existing offsets do not fall in good locations.

The other 10 footer - I didn't build it - is based on the Robert Morris 'recovery' kayak (you can find a survey in his book). Its similar to the retrieval but simpler to build (fewer chines) and the hull shape is different. Its similar to Wolfgang Brinck's recovery (but Yost style construction):

http://wolfgangbrinck.com/boats/tales/playboat.html

Its not as easy to handle (slightly less stable, no directional stability) but its faster and can be more fun depending on conditions.

: I am thinking about building a 10 ft kayak for my 12 year grandson using the
: Yost approach and some material left over Coverene from a folding kayak I
: built. Are you willing to share the offsets?? And is it suitable for an
: inexperienced paddler??