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Wave Power Fails To Live Up To Promise
the_newsbeagle writes: One of the leading companies developing wave power devices, Ocean Power Technologies, has dramatically scaled down its ambitions. The company had planned to install the world's first commercial-scale wave farms off the coast of Australia and Oregon, but has now announced that it's ending those projects. Instead it will focus on developing next-gen devices. Apparently the economics of wave power just don't make sense yet.
When I was a child, we had a nice wood boat. A ChrisCraft. The finish was getting pretty weather-worn so my father took it to a guy who refinished boats to get it done. He specified brass screws, just like the original. The refinisher said, "Everybody uses stainless steel these days. They're just as good." My father reluctantly let him use the stainless steel screws.
The boat was moored by strong chains to a dock in the ocean. (You had to leave lots of play in the chains so the boat could ride up and down with the tide.) A few weeks later, by family got a call from the SeaBees. They had found the boat, dangling underwater by the chains holding it to the dock pilings.
The seawater had eaten the stainless steel screws right up. It only took a few weeks.
The original screws were probably bronze, not brass. Bronze has no appreciable zinc while brass contains a lot of zinc. Immersed in sea water, brass will dezincify and corrode.
Most marine raw water systems use bronze fittings for this reason.
Stainless isn't suitable for below the waterline applications because the chromium can't form a protective oxidization layer due to the lack of oxygen exposure.
Your boat would have sunk with brass or stainless screws.