We are working on a seastead design that will have a 39 by 16 foot living area above the water.
The living area will have a main structural frame that is a rectangle 39 by 16 feet.
There will be 4 foot wide columns/floats that are about 20 feet long going out from 
from the 4 corners of living area and down into the water at 45 degrees, which half of
each column under water, providing the buoyancy.  From the bottom of each column there will be 
2 cables going to the adjacent corners to hold it in place.
So it is like a tiny tensegrity oil platform for one family.

Please try to estimate the maximum forces from the floats and the cables on the corners
of the frame, even in huge waves.

Imagine we use duplex stainless steel for the floats and the frame.
Imagine we use 1/4 inch thick duplex for the floats.

What would you recommend for the design of the  frame?
How much would the frame and the floats weigh?
How much buoyancy if the floats are half under water?

After subtracting the weight of the frame and the floats from the buoyancy how much extra buoyancy 
do we have for everything else we need on the seastead?