XPost: alt.sci.nanotech   
   From: my-name-here@schmeeky.co.uk   
      
   Andrew James Alan Welty wrote:   
   >>I had an interesting idea today for an artificial island. Instead of   
   >>building up the sea bed, why not build a diamond or carbon nanotube wall   
   >>that completely encloses an area perhaps 100 square miles or more? The walls   
   >>would rise up from the ocean floor and extend perhaps a couple hundred feet   
   >>above sea level. Once the wall is completed, siphon out all of the water   
   >>within it and you have a dry patch of land to build on. The average depth of   
   >>Earths oceans is only about 2.5 miles, so there should be plenty of places   
   >>to do this if we want.   
   >   
   >   
   > Why does the water need to be pumped out at all?  Another option would be   
   > to allow water to flow through and just build on the top.  This would take   
   > more material to close over the top but would also take less for the walls   
   > as they wouldn't need to be solid and then you wouldn't need to pump   
   > anything out.  Which way would be more practical I couldn't say though.   
   >   
      
   So something like a giant oil rig? You wouldn't really need it to have   
   'walls' at all then, it would make more sense to just use a grid of   
   support columns. There wouldn't be any pressure differential (the water   
   wouldn't be held back) so this shouldn't be a problem. The material to   
   close over the top wouldn't need to be anywhere near as thick as the   
   walls would have been. Definately a cheaper and more practical option.   
   If you really felt the need to reclaim the actual seabed, you could   
   dredge it up and stick it on top, although I suspect that topsoil from   
   some solid ground would be more use.   
      
   Mike.   
      
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