We are working on a seastead design.
This it is has legs going into the water like a semi-submersible but they
are foil/wing shaped to move through the water with less drag.
There are 3 legs so it is a bit like a trimaran with a very soft ride.

Above the water there will be a big triangle frame.  The
left and right sides will be 80 feet long and the back part of the triangel will be 40 feet wide.
The triangle frame will be a truss structure that is 7 feet high (floor to ceiling).
It will be enclosed and the whole inside the living area.  Lots of glass to see out.

There will be 3 floats/legs/wings that will be the buoyancy.
Each leg/wing will 19 feet long and have a NACA 0030 foil shape with 10 foot chord and 3 foot width.
This makes for a "small waterline area" similar like a small oil platform but one that can move through the water easier because of the foil shape.
Each of the 3 legs will be attached to the underside of the big triangle near one of the 3 points (but the total top of the
leg will be inside the triangle) and going down into the water.
The 3 wings will all be parallel with the blunt or "leading edge of the wing" forward  so it is easy for the seastead to move forward.
Each leg will be 50% under the water (so 0.5 * 19 feet) and the top 50% out of the water.
On front of each leg on the top half that is out of the water will be a built in ladder.

There will be 6 RIM drive thrusters of 1.5 foot diameter, one on each side of the 3 legs/wings about 3 feet up from the bottom.
These RIM drives will have the flat sides toward the frong and back of the seastead.

On top of the roof there will be solar all over.

Behind the back near the center will be two supports going out and 2 ropes going down to a dinghy.
The dinghy is a 14 foot RIB boat.  It is sideways against the center of the backside of the living area.
When the seastead is moving forward the dingy is shielded from the wind by the living area.
Also behind the back on the left and right of the dinghy will be a deck that is 5 feet wide extending beyound the back of the triangle.

There are 3 stabilizers that look like a little airplanes, one attached near the back of each main seastead leg.  
The little airplane has a 10 foot wing-span, 1 foot chord, the body 6 feet long, and the elevator has a 2 foot wing-span and 6 inch chord. 
A small actuator makes the elevator angle up or down so it can adjust the angle of 
attack of the main wing of this stabilizer without needing a large actuator.
While the thick part of the leg is 3 feet wide the back where the airplane will attach is very thin.  And to get the airplane's
center of lift to balance on the pivot a notch into the front/center of the wing only has to go about 25% of the chord of the wing.






We made a 1/10th scale model of the above seastead design.
The wooden triangle is 8 feet on the 2 long sides and 4 feet on the short side, all made from 2x4 boards.
The 3 foam floats/legs/columns are 22.8 inches top to bottom and about NACA 0030. 

Here is video of the scale model tested in some waves:

https://www.youtube.com/watch?v=rLqTSadJ118


This video has been not been slowed by the Froude time scaling factor.  It is the original speed.

Try to estimate the wave heights in the video and say what 10 times that would be for full scale.
Please try to analyze the experimental results of the video and tell me as much as you can about how the full scale
would move compared to a 50 foot catamaran or 60 foot mono-hull.  See if you can figure
out the accelerations and compare those to accelerations on those boats.

There will eventually be stabilizers, which are not yet in the model.