We are working on a seastead design.

Above the water there will be a big triangle frame.  The
left and right sides will be 70 feet long and the back part of the triangle will be 35 feet wide.
The point opposite the 35 ft side is the front.
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 are 3 legs/floats/foils/wings that provide the buoyancy, so it is a bit like a trimaran but with a very soft ride.
Each leg/wing will 19 feet long and have a NACA 0030 foil shape with 10 foot chord and 3 foot width.
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 so that the lower half is in the water.
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.
The 3 legs will all be parallel with the blunt or "leading edge of the wing" side facing forward so it is low drag 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 the top half of the front of each leg, so 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 front 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 with an electric Yamaha HARMO outboard.  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 beyond 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 12 foot wing-span, 1.5 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.
This is really the "servo tab" idea.
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.

When the seastead is going to be staying in one place for awhile, we can put down 3 helical mooring screws and give the seastead tension legs 
so it becomes nearly stationary when parked.

Two seasteads will be able to connect together with a walkway, one behind the other, so that while underway 
people can move between seasteads, enabling a real community.   






I would like to be able to simulate seasteads like the one above in waves as 
as was done in this video:
   https://www.youtube.com/watch?v=PsPeasVy248

What open source software can simulate simple designs in waves as was done in that video?
That video is one of my earlier designs.  

I would like to be able to simulate in higher and higher waves and be able to tell
what movement and accelerations are at different points in the seastead.
But I want to be able to visualize it so it is easy to understand
how things go wrong and what I might need to do different.

Another problem is that in my models with 19 foot legs that can go from 1/2 in the water to
where it is almost all in the water, so some "linear assumptions" like in Boundary Element Method (BEM)
used in some models may not be accurate enough for my needs.
It is an important question/experiment to see how much these legs damp heave and roll type motions.

We have a computer with a very good GPU.
So we could do some compulationally intensive simulations at no extra cost to us.  Would be fun really
to make use of this systems power.

I don't care about simulating propulsion or the stabilizers for now.  The important question at this point is 
how stable is a design on the waves and at what wave level might something fail.

I would like a high level of engineering accuracy in the simulation.  

Project Chrono uses BEM so I worry it is not accurate enough for my unusual shaped models.
I hear Chrono::FSI-SPH might be better for my needs.   If we use this then Chrono is not using BEM?

Capytaine and MoorDyn is another recommendation.  Both of these can be used from Python.
Claude Code and Cursor.ai can help me with Python scripts so it might go fast.

I was told that Blender can be used but that the physics simulations are not at all accurate.
Is that still true or has someone made something so I could do a reasonably accurate simulation
of a simple seastead model using blender?  And Claude Code or Cursor.ai could help me with this?

I was told maybe using WEC-Sim and MoorDyn could work.   Does this seem like a good way to go?
Would these let me make videos showing how a seastead design would work in the ocean?
Could WEC-Sim and MoorDyn handle this sort of thing?   It seems this needs MATLAB which
is not free (please estimate cost for a non-student in Anguilla).  Also seems this 
requites "Simulink" add-on and "Simscape Multibody" so there is a high total cost.
Really this should not be on my list of open source solutions. 

DualSPHysics is another one mentioned.  For this they recommend a system with a good GPU but we have one.
Does this seem good for my needs?

OpenFOAM is another one that can make use of our compute cycles.

Is there any other free software that might be a better way to simulate, test, and visualize my seastead design ideas?

I like Claude Code and it has been a big help in setting up projects like this in the past
so I am not to worried about something that may take some effort to get to first simulation.

Please compare the different free software options (not just those listed above).  Try to estimate how long it would take to get a
simulating working in each (assume we have Claude Code helping).   

I generally like Linux but we have Windows machines we can use if needed.

Also, after we get a simulation working for one seastead model design, how hard will it be to get
another simulation running for a different model type?