K/proa

	Model No.3 was sailed in 1990. It was intended as a looks-like/works-like example of the solution, minus human amenities. The keel/rudders were moved by servos using 2-channel remote control.

It utilized the traditional method of tilting the mast to position the sail at the opposite ends of the outrigger hull. This was not an adequate solution, as it is troublesome and couldn't be considered a safe maneuver in a strong wind and heavy seas. Moving the sail from one end of the outrigger hull to the other was a continuing problem until a solution was found for the 2nd iteration of Model 3.

	The overall performance evaluation of the 1st iteration was hampered by insufficiently large keel/rudders. While sufficient in area to balance the lift of the sail, they were inadequate to turn the long, narrow hulls. The model sailed along close-hauled, changing course to follow the wind shifts.

The 2nd iteration of Model No.3 improved the design of intra-hull components, and established the amount and kind of relative movement of the hulls. From the beginning, I had accepted that in order to get enough space between the hulls for force balancing with a reasonably upright sail, the intra-hull connections would have to be long and flexible. The task was to control the bending within predefined limits. On the 2nd iteration, I rigidly affixed all three poles in the main hull. At the outrigger hull, the center pole connection permits rotation and the outer pole connections permit rotation and lateral (pole axis) displacement. The stresses in this arrangement are predictable and within the limits of conventional materials. And the usual problem of making rigid multihull connections is avoided.