I would like to take a crack at reworking the 
sky, water surface and ocean depth system.
Quite simply the sky will have + numbers, the
surface being 0 and the ocean depths being -
numbers. I would keep track of it all in a
mapping within a daemon. Each location would
be tracked with the height (or y in the x,y,z
format)being the first key in the mapping.
Another mapping would be the value for those
keys. The key for the inner mapping would be
({x,z}) for the width and depth dimentions.
the value for the inner mapping would be who
or what is at that location. Once that location
is empty, it gets deleted from the daemon's
mapping. 

(["height":({width,depth}):
([location content: 
({ passengers, objects onboard, etc }) ]) ])
