We are working on a seastead design.
The design goals are discussed at http://seastead.ai/ai/seastead.goals.html

DESIGN IDEA

This is NOT a normal boat hull shape, but it is a bit like a trimaran in that their are 3 floats.



Above the water there will be a big triangle frame, 80 feet on a side.
What is the area inside the triangle in square-feet and also in acres?
The triangle frame will be a sort of truss structure that also doubles as a 4 foot high railing to keep humans from falling off.
We will call the 3 points on the triangle "front", "left", and "right".
And the edge between left and right we will call "back".

At the same height and in the same style as the triangle-frame/railing will be foundation frame for a rectangular living
area.  The this living area frame will be 14 feet wide and as close to the front as you can be 14 feet wide
inside the triangle.  It will extend all the way to the "back".   
How long will this long side of the rectangle be?

The living area will be 8 feet height, with the bottom on the rectangular frame above.  Lots of windows in the
font and back and some along the side.   
How many square feet will this living area have?

There will be 3 floats/legs/wings that will be the buoyancy.
Each leg will 19 feet long and have a 10 foot chord and 4 foot width.
Each of the 3 legs will be attached to the underside of the big triangle near one of the 3 points and going down into the water.
For each leg will be 50% under the water (so 0.5 * 19 feet) and the top 50% out of the water.

The bottom of the living area in the same plane as the top of the railing and living area frames.

Across the bottom of the railing frame and living area will be a netting like on some catamarans.
There will be some steps going down from a door in the living area to the netting (about 4 feet down).

There will be 6 RIM drive thrusters, one on each side of the legs/wings about 3 feet up from the bottom.

There will be solar on the top of the living area and also fold down panels on the left and right sides.
In the picture have the fold down panels up and level with the top of the living area.  
The living area is 8 feet high and the fold down panels go out 8 feet.

Centered on the netting to the left side of the living area will be a 14 foot RIB boat with 1 outboard motor.   
On the triangle frame next to the boat will be a davit/crane for loading and unloading the boat.





The pieces can all fit in 40 foot containers, so shipping is reasonable, and assembled in a shipyard.

I am looking at 2 choices for the metal:
    1)  Duplex Stainless Steel (e.g. 2205) 
    2)  Marine aluminum 

Please discuss the weight, cost, and life expectancy of these 2 choices.

Estimate the total "installed watts" and the watt-hours we might per day in the Caribbean.
If we wanted to be able to store 2 days worth of energy in LiFePO4 batteries, how heavy 
would the batteries be?  We would split this weight among the 3 floats, keeping weight wide increases rotational inertia
and so reduces motion from waves.  The weight of the triangle frame is widely spread so also has great rotational inertia.
If we used a days worth of stored energy evenly over a 24 hour period how many watts would we have?

We will have 3 separate solar/charge-controller/battery/inverter systems so a problem with one
does not leave seastead without power.  Can have connections between them with breakers to isolate in case of trouble.

Imagine we are in high winds and turn the seastead to point into the wind.  What sort of 
drag would we have for 30, 40, 50 MPH winds and how many watts would it take for our
propellers to hold the seastead stationary?

Now imagine that we use the 3 wings like keels or dagger-boards and aim across the wind and just a little bit up.
How most of the wind force gets transferred to the wing/keel/dagger-board.
In this way how much wind do you think this design could still keep control in?

For a normal day in the Caribbean estimate the average watts power draw of all electrical components.
How much percent extra solar power do we have?

If we use the "extra power" to run the thrusters what cruising speed could we maintain for 24 hours/day?

Imagine we get a company in China to make the body and legs, and probably get other parts from there as well.

Please estimate weight and cost for each of these:
 1) legs
 2) body
 4) 6 RIM drive thrusters
 6) solar panels 
 7) solar charge controllers 
 8) batteries
 9) inverters
 10) 2 water makers and water storage
 11) air conditioning (AC) - maybe 3 units for 3 rooms but only using 1 at a time 
 12) insulation
 13) flooring, cabinets, kitchen stuff, furniture, bathrooms, bedroom
 14) waste tanks
 15) glass and glass doors at ends
 16) refrigerator
 17) biofouling weight gain in first year
 18) safety equipment
 19) dinghy
 20) 2 sea anchors 
 21) kite for propulsion.  Can use as backup, fun, or extra speed - perhaps stack 20 kites of 6 foot each 
 22) 8 air bags in each leg so for extra safety in case of leak in leg
 23) 2 Starlink  - need a backup
 24) trash compactor
 25) davit/crane/winch to lift dinghy out of the water
 25) anything else to finish it out

Also totals for weight and cost.  

Please estimate:
   1) how much the body would tip in terms of feet higher or lower between front and back of living area
   2) Gs felt due to waves in living area spot located at the center of the triangle 

for the following types of waves:
  1) 3 feet 3 second period
  2) 5 feet 5 second period
  3) 7 feet 7 second period

both if the wave is coming from the front and also if it is coming from the side.

What length catamaran would have comparable inside square footage to this seastead?
About how many times the cost would that catamaran be compared to this seastead?
Would you agree that this seastead will pitch and roll less in 7 foot waves than a 100 foot catamaran?

What do you think this could rent for per week?
How much of the rental would be expenses and how much profit (ignoring capital cost or depreciation)?
How many weeks of rental profits would it take to pay for the seastead?

In flag of convenience countries like Panama and Liberia could we register this as a "trimaran yacht" or
would it be harder than that? 

FEEDBACK
Also feel free to give any general feedback on:
  1) viability of current concept as a profitable business product
  2) how concept might be improved
  3) how big a market niche this first product could become
  4) Do you think this is fast enough that with weather forecast accuracy in 2028 we should be reasonably
     safe from storms in the Caribbean if we are at the southern edge during hurricane season?
  5) Are there single points of failure that you think need to be further addressed or is what we have good?

Summary section.
  For a summary at the end please list:
    1) estimated total cost for first unit and cost each if we ordered 20
    2) average solar produced, average solar used not counting propulsion, average power left for propulsion
    3) lbs extra buoyancy for customers and their personal stuff
    4) speed in MPH this design can average 24/7 in Caribbean