First off I wanted too see if it was possible to build pulleys out of PVC pipe. I when out looking for scrap pieces of pipe that builders no longer wanted. It didn't take too long to find some.
The pulleys consisted of 2 PVC pipe cut-offs, one inside the other. The smaller pipe was glued to an old CD and functioned as the bearing around which the larger pipe rotated. The pictures above show the whole process. Unfortunately these pulleys were too light-weight for heavy lifting. The main weak point is the CD as it can't handle the pressure, as expected. Another way must be found to construct pulleys cheaply and out of recycled material.
Secondly I wanted to see how all the plans fit together. The whole setup was done on land because testing in the ocean first was deemed a little too risky for a first draft.
The major change to the design was that bicycle parts were imported into the idea. The original shaft generator idea was not that practical. Too much copper would have been needed to cover a pipe of a few meters long. Also, having a rotating wheel allows for inertia. So the bicycle sprocket idea came to be. It's a cheap one-way bearing and since a chain connects to it there is no slippage. It also allows for better scalability since additional sprockets can easily be added to the rotating shaft. The pictures below show the concept better.
The pulley guides the rope from the float to the bicycle chain where it's firmly connected. As the wave pulls the floats up the rope will pull the chain which will drive the sprocket. As the wave drops the counter weight at the end will return the chain to its starting position.
Since bicycle sprockets are mass produced they are rather cheap (R25) and second hand sprockets are not that difficult to obtain. The same goes for the bicycle chain, a new one sets you back R85. I went into the first bicycle repair shop that I saw and asked them if they had any throwaways. They had no problem supplying me with everything I needed free of charge (social business already at work).
The picture above shows how the sprocket and wheel was mounted to the bottom of a work table. Thanks to Hein and all his bright ideas!
These pictures show how the second hand inner tube from a bicycle became the belt to drive the generator. The generator used was a 600watt from an old wind generator. In the end the generator only produced a small charge but this was expected. The power of the design would only start to show if a few of these were set up in series.
There were a couple of things discovered through the construction: