XPost: alt.sci.nanotech   
   From: cdorrough@nortonconsultants.com   
      
   "Michael Houston"  wrote in message   
   news:dlfmm1-fth.ln1@lemur.spacesquirrel.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.   
      
   Why even bother with the support columns?  The technology already exists to   
   make a huge reinforced concrete bathtub over a 1km in length, and containing   
   all the fresh water storage you could dream of (fresh water gives added   
   buoyancy), power generation and desalination plants, an artificial harbour   
   and sufficient low-rise housing and parkland for a few thousand people..   
      
   .then again, you could bite the bullet and make it out of steel with a   
   point up one end, add some thrusters at the back and sail the thing around   
   the world under it's own power! (Oh, that's already been done? Darn! ;-)   
      
   Definitely the future.   
      
   Cameron:-)   
      
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