Shaping

I started with a 96x28x16 inch block of 1lb/cubic ft EPS foam (styrofoam). I was able to get my block from a foam place that specialized in architectural pieces, and paid $80. You can get 2lb density foams, but they are more expensive, take longer to shape, and will add more weight to the boat (but the final shape will be less fragile).

Rocker

The rocker was cut into the block first. I had taken a picture of the waveski, and traced the outline on the computer. I then printed this out onto overhead transparency and used an overhead projector to project and trace the outline onto 1/4" hardboard. This let me scale the basic rocker pattern to the lenghth of my foam block (which was longer than the waveski).

The rocker was cut by placing templates on both sides, and drawing a hot wire cutter across.

Outline

I then did the same thing with the outline (taking the clever step of bending the template material to the rocker while projecting the outline, so that the flat 2D projectionn of the outline in the photo I had traced was reversed).

When the outline was cut by hot wire, I left about 1cm of extra foam around the drawn line - I would shave this down to the traced outline only when I got to the rails, in order to protect the true outline from dings during initial shaping.

Deck

The deck was the most time consuming and difficult part to shape. I had to consider my body position inside the boat without being able to get inside. I took some basic measurements of me in my standard kayak sitting position and placed wooden rods into the form at these points to give me a set of landmarks (any drawn marks would be quickly sanded off). I also tied a string from a rod at the front and rear centerlines to allow me to keep track of the centerline along the length of the shape.

Later I also cut some material into the shape of the cockpit, so that I could prepare a flat surface for adding on the cockpit rim.

The deck doesn't have tons of influence on the boat once it is on the wave - thats mostly the hull and rails. The side walls did need to be angled in so as to keep the rail exposed when leaning into the face of a wave, but otherwise the deck was constructed for comfort inside (plenty of footroom) and volume balance while paddling out. Because the seat was so close to the stern, this required a large 'hump' in the back to avoid unintended backenders while paddling out and stability in foam. I erred slightly on too much volume in this hump, because too little would have been a disaster.

To shape the deck I used a combination of tools. First I used just a serrated kitchen knife that I rasped back and forth which was good for removing a lot of foam quickly but left a very rough surface. I then shifted to a combination of very rough sanding blocks (36 grit) and Sureform rasping tools before the final sanding, there is not much point in sanding beyond 120 grit or so except on the rails. It is hard to get things perfectly symetrical - I did the best I could just by viewing from many different angles.

Rails

The rails were shaped by eye and by feel. First I used the sureform tool to bring the outside of the rails to the ink outline. Then I hand sanded the hard cornered rail down varying amounts along the length of the boat. Be very careful around hard rails in the shape once you have them to where you want - as they are very fragile. Given the fine nature of this, I almost exclusively hand sanded the rails with 120 and then 320 grit. Even if you want super hard edges, you can not get fiberglass to bend around extreme corners so keep at least 1/16 of an inch bend around corners. You can pour harder edges later.


The final shape sanded