Surfproa 1 is a Slalom Canadian canoe created by the Rivers Canoe Club, NSW and named Platypus, which I converted to a proa by adding an outrigger (ama). I used it to obtain experience in negotiating beach surf in paddle-power craft.
My first experience in surf in Surfproa 1 – my mate and I were surprised by a big breaking wave and we dived overboard and deep to safety. When we surfaced we saw Surfproa 1 floating upright. So following this experience, I turn Surfproa 1 side-on to a breaking wave, and safely travel ashore.
This manoeuvre is not my invention – it is a slalom canoeing technique. Slalom canoes have rounded smooth hulls, no keels and require little effort to manoeuvre in turbulent water. But they require paddle-support-strokes to prevent rolling-over. To travel ashore the slalom canoeist turns the canoe side-on to a wave and supports the canoe upright by leaning into the wave and applying support strokes to stay upright. Support stroke – patting the wave with the flat face of the paddle.
This publication my Surfproa experience is motivated partly by the drowning of fishermen along the South Coast due to capsize of their trailer-boats caused by wave encounters. I guess these boats capsized when pushed sideways by a wave and the chine of their vee-bottom boat and flat topsides, caused the boat to tip over. Two of my family survived a boat capsize, caused by a bombora wave. Bomboras suddenly appear out of a flat sea when an ocean swell encounters an isolated underwater reef – which attracts fish and fishermen. Their locations are not publicised and they are probably responsible for most capsizes. They are a dream waves for surfies and they know where they occur.
During the last 25 years I constructed three Surfproas – starting with a 500mm diameter hull followed by a 700mm diameter hull and finally an elliptical hull cross-section of 1000mm beam. I have not tested them side-on to a breaking wave.
The Surfproa hulls are rounded and smooth, so when these hulls are pushed sideways in water, they do not produce forces causing capsize. To minimize Surfproa hull construction work I made a mould and from it constructed fibreglass bow and stern sections and joined them to a plywood centre-section rolled to fit these fibreglass end sections. Photo 5 shows the hull construction with one fibreglass end section attached to a plywood centre section.Trials of Surfproa 2 are covered in the June 2010 instalment of Project Windrigger published on the Amateur Yacht Research Homepage website. The outcome of these trials lead me to build a wider and flatter rounded-hull resulting in creation of Surfproa 4 – which has an elliptical cross-section hull.
Construction of Surfproa 4 was produced using an internal mould produced by fibreglassing over the wood/plywood plug is illustrated under construction in the photo. Its bow and stern ends were constructed of fibreglass clothe and epoxy applied to the inside surface of the mould. This was a tedious operation requiring glassing on the horizontal surfaces and waiting for it cure before rotating the mould to complete the glassing operation. Next time I shall try glassing over the plug.
Surfproa 4 is rigged to carry a biplane sailrig like the one shown in the photo, and leeboards.
The shape of the hull ends was produced by assembling plywood cross-section of identical elliptical shape and positioning touching an ellipse drawn on the deck level surface.