Update 5th Dec 2011:
I have now tested the yuloh with my boat and can report that I made a mistake with the choice of paddle material...a scrap piece of UPVC cladding. I chose it because it is easy to cut and will not rot,
but hadn't bargained on it being so buoyant. The trouble is, it floats so well I was struggling to keep it under water!!!!!!!!!
My next thought was to
cut up a large polyethylene chopping board. This also floats having a relative density 0.93 or so, much greater than the UPVC and greater than Ash wood at 0.54 or Birch at 0.67. Looking at Bamboo itself, that is 0.3 to 0.4, so not a good choice either in terms of keeping it submerged.
(2nd Dec 2011)
I have a 3m long folding boat which you can row, sail, or use with an outboard motor. Rowing is OK but as you are facing backwards it is not that good for exploring...so I turned round and rowed forwards! Not as efficient maybe, but far more interesting and you are less likely to collide with something.
I made a sail out of some inexpensive tarpaulin using instructions from the Internet, and have since found that it would be useful to still have power and maneuverability even when the wind drops. The problem is that of having too few hands for managing the sail and two oars all together. Hence the idea of sculling with one oar like in a Venetian gondola, or a Chinese junk. It is also useful in narrow channels as two oars are unmanageable.
The oar has many names, 'Yuloh' being used in the Orient. It works like a slow propeller blade, reversing direction with each stroke. It has a curved handle, and this is a vital feature to enable easy sculling and good propulsion.
Here's a good idea of what it is and how it works:http://www.youtube.com/watch?v=UjyE7dyR2X4
There are many photos on the Internet, but very few clear instructions on how to make one. This Instructable hopes to fill the gap for an inexpensive oar that can be made mostly from scrap.
The first problem to solve was what to use for the main 'pole' part, and how to get the curve. After some time the inspiration to use a thick bamboo pole emerged. However, firstly, I did not have one, and secondly it would be difficult to factor in the bend. I expect a green bamboo pole would be fine, but they are not available here. Undaunted, it occurred to me that by strapping six or so small diameter canes together I could achieve what I wanted.
The blade of the oar is made from a scrap piece of white UPVC cladding about 10mm thick.