I have several boats that work well with traction kites. One is an old (circa 1938) wooden kayak built by my grandfather. He would roll over in his grave if he knew the mahogony sheeting was removed to lighten it, then a hole cut in the bottom to accommodate a Hobie foot pedal mechanism. A through the hull rudder and a recumbent seat finished the boat.
The second configuration is a Walden Vista kayak which is 12.5 feet long. This kayak lacks a rudder so a small wooden rudder was made to slip over the stern. Tied into position with lines to bungee holders on the deck it has parachute cord stretched to each foot. This rudder system works well. I have two Vistas set up identically. The two boats can be used without the rudders if you tie the boats together, one slightly behind the other. The bow tied to one cockpit, and the stern tied to the opposite cockpit. This staggered arrangement allows two people to work together, one up front flying the kite, one in the back steering. When done the configuration breaks apart easily.
A third configuration is also a favorite in warmer water. It is a windsurfer which has
a seat on it. The Hobie pedal mechanism is also fitted to this boat. The windsurfer has
a centerboard which helps when tacking to wind.
It is best to learn how to fly the kite at your local high school. Pick a small kite, never more than about 2 meters square area for safety. Believe me- it will often be too much kite. If you get extremely comfortable with it and the weather is warm, move to a 4 meter kite to really skip along. I prefer to make my own kites. The NPW variety work very well and are cheap to buy or cheaper to make. Search the web for NPW kite plans. There are several easy programs to run which will turn any old piece of fabric or plastic into a device that can produce real pull. At the school learn to fly it in a figure 8 (on its side) pattern. Flying the kite fast will significantly increase the pull of the kite... it is an airfoil and flying it fast produces more lift as the higher speed wind flows over the airfoil. Use a 4 line kite reel. This allows you to wind up the lines, hold the kite in the air and relaunch it from your kayak. Drop to the bottom of this page for kite reel photos.
With a rudder you can steer cross wind until the kite launches, down wind if the pull is too strong, and slightly up wind if you are lucky to have minimal waves. If you choose to go down wind you will notice that your relative wind speed may drop below what is required to actually fly the kite. Under these conditions you must either come back to a broad reach, or pick the kite up from the water and launch it again. It is much easier to kite kayak with a rudder. Lacking a rudder, some launch a small sea anchor to produce sufficient drag to slow down the boat. When the wind increases, pull in the sea anchor. For those non-nautical... a sea anchor is a small parachute with sturdy leads on it. A foot in diameter sea anchor is sufficient to slow any kayak. Use of a sea anchor allows you to use a single line kite without guidance while fishing. I rarely use a sea anchor. It is much more fun to go faster.
Turning is interesting. If you fly the kite behind the beam, the kayak will of course
eventually travel backwards. If you steer the stern into the wind, you learn how to do
a sort of K turn that keeps you from loosing 'ground' if you are trying to stay upwind.
A larger kite won't help too much, save it for skiing on a nearby frozen lake in the winter.
Your kayak will make it to boat speed easily with a 1.2 meter squared kite. Never tie
the kite to the boat or the pilot. Always hold it in your hands so it can be easily
released. There are several reports on the net of injury or death from use of the larger
kitesurfing kites with kayaks, most were somehow attached to the boat. ALWAYS wear a
life preserver. It is best to follow a shoreline when learning. You are more likely to
obtain assistance or be able to swim or paddle to shore for safety.