These pages detail the methods that Jenny and I use to build proprietary composite kayaks for our own expeditionary use. The boat pictured below, Siku kayak, emerged from our workshop the spring of 1996 and traveled 1,400 miles along the West and North coast of Arctic Alaska.
The Construction of Tempest
The process begins by computer designing the kayak. Hand lofting from an existing set of tables would also work, but the computer is easier, faster, and more accurate. It also allows us to configure the design to our specifications, and to predict its performance.
The computer program (written by myself, former aerospace engineer) outputs data in the form of mold frames and bow & stern profile pieces. This can be output to AutoCad for machine plotting a set of full-sized patterns, or simply printed as a table of offsets for hand plotting.
We hand plot our offset data onto a sheet of particleboard. The frames do not become part of the boat. They simply define the mold. The horizontal reference is my designed waterline for the kayak loaded, in this case, with 637 pounds. This is our target weight of boat, ourselves, cold-weather clothing, equipment, drinking water, and food for three weeks.
After plotting the frames on particle board we cut them to shape. Then we mount them onto a "strongback." This is a sturdy ladder-like structure on legs.
This photo shows the bow profile piece, notched to accept the small frame.
When all the frames are positioned, they are checked for fairness with a long batten. Thanks to computer accuracy and careful lay-up, adjustments are seldom necessary.
Next we attach stringers to the frames, as though strip-planking the mold. Except that the stringers are spaced apart.
We have covered the stringers with structural foam. The foam will become the core for a sandwich of carbon.
Cored, one-off construction is one of the easiest ways to build. This is because part of the mold - the foam - becomes part of the boat - the core. The method produces a somewhat heavier boat than a non-cored, but it can be stronger if done correctly. And it offers fair insulation to cold water - a genuine consideration for our type of paddling in the Arctic, and excellent built-in flotation - a tremendous safety feature for any boater.
Next we laminated strips of carbon. In this photo we have applied one full layer running bow to stern, and I am squeegeeing a second layer at right angles.
After the lay-up has cured, we separate the mold from the strongback. We lift the mold/layup assembly, roll it over, and rest it on a pad lying on the floor. Then we make a set of cradles to the shape of the hull, and attach them along the length of the strongback. And after nesting the mold/layup into its cradles we gently pry the mold out of the layup and set it aside.
This picture shows the layup seated in its cradle atop the strongback. We have applied two internal strips of uni-carbon end to end, and will apply another layer of strips laterally.
The kayak is nearly finished. The hatch rims, covers and hardware are built, the cockpit rims are finished, seats and rudder installed. The final step was to paint the deck white. All up, the boat weighed 75 pounds, which was not bad for an 18 foot, high-volume expedition double. We paddled it 600 miles along the coast of Arctic Alaska in 1995, and subsequently named it Tempest
, for all the storms it weathered.