There are diagrams on the web.
Posted by: bartc on Sep-20-12 5:21 PM (EST)
The best is an "Aleutine Pagaia", an Italian set of sketches in detail that Google will translate for you. But the diagram is self-explanatory.
It's actually easier to laminate up two pieces of stock than to carve a 2'x4', but either way works.
I made my first with Western Red Cedar, and believe me, that's the wood of choice. It's shockingly light, yet strong, easy to work, and both water and rot resistant naturally. I made my second with other woods and have found it a struggle by comparison with WRC.
The tool I used most, after using a bandsaw to cut the blank shape, was a Stanley Surform tool. It's a combination of a plane and a rasp, and you can get both a flat and a very helpfully curved blade (the 10" model, BTW). There's even a flat Microplane blade for it that works even better than the stock Stanley stuff.