I second that.
The standard long keel kayak that we all know has a couple of thousand years of development on it. They are long and thin because that is what works best. The Inuits didn't always have access to long pieces of wood so a short boat would have been much easier to build. But, they went to the trouble of building long hulls and time has proven them correct.
When you get into any kind of human powered boat the smart thing to do is to exploit the laws of hydrodynamics so the person supplying the muscle doesn't get worked to death. In general, longer boats are faster, have more glide, go straighter, can accomodate a wider variety of wind and water conditions.
Short boats (12-13 footers)seem to work OK if the proper hull shape can be achieved. Rotomolded plastic is ideal for these hulls because it can produce whatever shape is necessary to overcome short waterline problems.
If you go shorter than 12 feet you are getting into questions about minimum safe displacement like, how small is too small?
Retrieval and recovery boats were special use designs not intended for open water passages. And if you tried to paddle one along with standard length boats you would work a lot harder than they to go the same speed.

: There seems be two different opinions of these boats. One is they are very
: cool. The other is that they have very limited use.
: I have made one and gave it away as it did not get used. They are a very
: specialized boat. The behave very similarly to a white water boat. Not
: exactly something that will go strait for very long. In addition, they sit
: very low in the water, not like a 10 ft recreation boat, but like a white
: water boat.
: So as you can tell by now, my opinion is that they are too specialized to be
: general use. If Morris had only designed a 11-12 ft boat with stems deep
: enough to track well. Of cource, what I just described is easy enough to
: do yourself.
: As far as using found materials, the materials are quite cheap when purchased
: yourself anyway. I would love to try willow and actually have a tree
: growing in a pot specifially for this purpose. In about 5-10 years it will
: be big enough to harvest.
: Scott