We are working on a seastead design that will have a 40 by 16 foot living area above the water.
There will be 4 foot diameter legs/floats/columns that are about 24 feet long going out from 
from the 4 corners of living area and down into the water at 45 degrees, with half of
each column under water.   The legs/floats/columns will probably be made from 1/4 inch
thick duplex stainless steel on the sides and 1/2 inch thick on the dished ends.
They will have some modest pressure like 10 psi inside.

The bottoms of the floats will make a rectangle about 50 feet wide and 74 long.
From the bottom of each leg there will be 2 cables going to the adjacent corners.
The boyancy force is lifting up and the leg pushing against the platform leaves an outward
force that the 2 cables pulling in counter, so the leg ends up staying in place.
There will also be a cable making a rectangle between the bottoms of all the legs so we have some
redundancy in case one cable breaks.
The seastead is about 36,000 lbs I think but this is NOT a normal boat hull shape,
it is more like a tiny oil platform as far as drag.

We expect to use 4 low speed submersible mixers with 2.5 meter diameter propellers as 
thrusters, one on each leg/float.  There will be lots of solar and battery.
This should move at around 0.5 to 1 MPH plus any help from careful use of eddies and currents.





Imagine we change the body to one that is sort of like a big modular aluminum pipe.
Say round and 12 foot diameter and maybe 40 feet long with additional rounded caps on the ends
so overall around 50 feet.

This reduces wind drag when going into the wind and the round sides are not too bad for wind
from the sides or even a wave hitting from below.

We would like the parts to fit into a 40 foot container for shipping.


The body has to be able to handle the twisting forces if the front two legs are lifting more on the left side
while the back to legs are lifting more on the right side.


It would be nice if we could assemble this without welding. 
Probably around 8000 lbs payload inside but much of the heavy things, like batteries, we can keep near the corners.

Can you design such a thing?
How heavy would it be?
Can it be a bolt-tether or do we need welding?

Note that the legs are going out and with the cables have a bit of leverage sort of, so there can be a significant torsion.