Re: Even more basic construction ideas.



Adam Scriven wrote:
> 
> If the platforms have to be in the vicinity of half a km tall/deep...
> that's much more vertically massive than I was thinking...

I think it is important to correct this misconception
that .5km deep structure is needed.

The reasoning behind tower based strucutures is two fold --
1) safty and 2) comfort.

I'll talk about safty first.  The more energy the waves impart
to the floating structure, the greater chance there is of
a catostrophic failure.  By putting the bulk of the structure
bouyancy well under the waves, and the living quarters well
above the waves, the waves impart relatively little energy
to the structure, thereby dramatically reducing the chance
of a catostrophic failure.

I'll talk about comfort next.  Due to the reduced sensitify
to waves, the resulting structure has less motion and is
less likely to induce motion sickness on its occupants.
Yes, there are waves with wave lengths that are 1km long.
These are also long period waves.  A structure that 50m
to 100m below the surface would impart some long period
"heave" on the structure in the presense of 1km long
waves.  Some people will find such heave to be unpleasant
and others will hardly notice it.  Such a structure would
relatively immune to the vast majority of shorter wave
length waves.  This is strictly a motion sickness issue
and not a safty issue.

When people design structures for long term living on the
ocean they are going to have to make trade offs between
overall cost, safty, and livabability.  I suspect that
a tower that is 50m to 100m below the surface will be
extremely safe.  Additional insensitivity to long period
waves can be purchased at increasing cost by making the
tower even deeper.  I suspect most initial seasteaders
will pick the tower cut off based primarily on safty
concerns, not on comfort concerns.  The tower design
should still be substantially more comfortable than more
traditional boat designs in terms of reduced motion and
hence reduced motion sickness.

> What about having a platform like this, then:
> -take the top end of Patri Friedman's 0.5 - 5 acre number for a surface
> area (just because I like the idea of bigger platforms over very small
> ones for some reason)
> -put in a bottom at 400m (just to pick an in the vicinity of 1/2 km
> number)
> -I'm thinking it would be better to have the underwater sides be
> geodesic, made out of tubes or something.  That would allow them to be
> used for transporting fluids as well, if properly designed.
> -any ballasts that are necessary could be made from both air/water, as
> well as distributed lighter-than-water storage (so instead of storing
> the H2 and O2, for example, in one big tank, it's stored in many
> smaller tanks distributed around the underwater structure)
> 
> It's not at all what I had originally thought, but it "feels" better.
> *laugh* How's that for scientific.
> It's not solid to allow the water to pass through unimpeded as much as
> possible.  The bottom was added (no more inverted "U" shape) in talks
> off-list for added safety in the event of capsize (not an event I find
> very likely given the scale [especially if more than one are
> connected], but nothing is unsinkable I realise).
> 
> How does this float with everyone?
> Adam

My $.02,

-Wayne




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