Re: Underwater questions [ot]

G'day Stephen,

>I'm working on creating a background for a RPG set on a waterworld and
I
have 
>the fallowing questions:
>1)  What is the maxium practical speed for under water transporation?

I'm only guessing (I'm not an engineer), but I'd say it'd be a lot less
than the top speed possible in air (water has a lot more viscosity than
air). 

>2)  What does a person need to live and what should be in the under sea

>comunites?

Some form of plant to desalinate water, another to extract oxygen from
the
water and unless your in very shallow water you're going to need a very
good light source and lots of them as light will be attenuated very
fast.
You'll also need atmospheric pressurisation or a whole mega series of
stop
points going from one depth to another.

>4)  Would a submarine fighter (like from Sea Quest or Archemdian
Dynasty) be 
>practical?

Small subs already exist for research, thought they are quite often
remote
control and slow, so theoretically one could, but there's a lot of
design
hiccups to get over first I'd guess.

>5)  What is the best shape for a lander desgined to move though the air
and 
>go into the water?

Hydrodynamics and aerodynamics share an awful lot in common due to the
basics of fluid dynamics. Just remember to give it stabilisers so it
doesn't go into a spin once in the water.

>6)  What would be the best simulater for underwater combat be?

Underwater hockey.... ;)

>7)  Would "cralwers" be usable?

Depends, how deep are you planning to be? They'd be fine for a lot of
continental margin areas where the substrate is fairly firm
(rocky/coarse
sand). Though obviously they're not going to be so crash hot on reefs
themselves. However, once you get into the abyssal stuff you'd want
walkers
(stilts) not crawlers or you're going to send up a choking silt cloud
that
will clog EVERYTHING!!! I'd also watch out for the continental shelf
drop
offs, falling off one of those would be a $^%!&!

>8)  What does it take to do under water mining?

Usually a lot of lubrication muds (i.e. do it from the surface with long
drills), but there is some undersea stuff using dredges and grabs etc
(though most of that is still surface based I think).

>9)  What would be the normal shapes that buildings be based on?

Something that distributes its load very well so as not to be crushed.
I'd
also avoid building anything in the range of the thermocline (about 50m
down) for navigation/camouflage reasons - either stay above it or below
it.
By the way if you're above it and using diffused light then I'd watch
out
for the seasonal phytoplankton blooms as they could mess things up big
time.

>10) What type of weapons would work (lasers are out, but what about
Sonic 
>weapons)?

Sonic weapons would, but they'd be a two edged sword you'd have to have
very good focusing and receiving blocking equipment if you didn't want
to
stun/hurt your own troops. It would also be good for confusion (bit like
a
smoke screen effect) as humans can't determine directions from sound
underwater as its moving too fast for our ears to discern differences as
they can in the air. You could potentially use it for long range
communication or jamming via bouncing it off the thermo-, pycno- or
salocline - it'd be a pretty neat trick though as whales are really the
only things to have figured out exactly how to do that yet.

Plain old explosions and projectiles would work fine too, with a couple
of
provisos. 1) Make sure your troops are either inside a structure or have
some pretty amazing armour/cushioning mechanism before letting off an
explosive (believe me suddenly feeling water trickle down your throat
because your eardrums are busted is NOT nice). 2) Make the projectiles
bigger than 2-3cm otherwise they're going to be effected by the water
viscosity (very small things moving through water, would be like us
swimming through honey).

Hope that helps

Beth

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Elizabeth Fulton
c/o CSIRO Division of Marine Research
GPO Box 1538
HOBART 
TASMANIA 7001
AUSTRALIA
Phone (03) 6232 5018 International +61 3 6232 5018
Fax (03) 6232 5199 International +61 3 6232 5199

email: beth.fulton@marine.csiro.au