Creating artificial "islands"

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.

Will it work? Is diamond strong enough?

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.

"Michael Houston" wrote in message
...
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:-)

"Cameron Dorrough" wrote in message ...
"Michael Houston" wrote in message
...
Andrew James Alan Welty wrote:
...snip...

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:-)

And the past. About 1963, at North American LA Division, I had
my space transport team design a floating launch site with
submerged "piers" and relatively narrow columns to support the
lighter superstructure. The narrow columns minimized wave motion.
Ninety percent of the buoyancy came from the submerged piers.
These floating piers were modular, cast concrete cylinders. Les
Hendrix--conceptual layout boardman supreme and now deceased--
got a big kick out of the approach and used to say we should
advertise it as: "Take an island for a cruise."

But the huge floating bathtub isn't a bad idea either. General
Dynamics considered getting an overage tanker and flooding it
with water. It was to be an Atlas sea launch facility.
Something that large and massive is also quite stable.

Best regards,
Len (Cormier)
PanAero, Inc.
(change x to len)
http://www.tour2space.com

"Bootstrap Bill" 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.

Will it work? Is diamond strong enough?

Siphoning out all the water would require 2.2 x 10^18 joules of
energy. If the wall were to break, the energy released would go into
making a gigantic tsumani, something on the order of hundreds to a
thousand meters high. Which would utterly annihilate any coastal
cities--just imagine a kilometer-high wave coming at Washington D.C.
or Los Angeles or Tokyo or Calcutta. The nations of the world would
never allow it to be built.