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.   







We are really trying to get a lot of solar area, living area, and stability for the weight of the design.
The idea is that costs basically scales with weight.  For stability a small waterline area helps
reduce the impact of the waves and make the stabilizer have a bigger impact.  However, the longer
the legs go into the water the more drag they have, and the slower we will go, and so the
less impact the stabilizer will have.

Please make and run a program or spreadsheet that helps search for optimal tradeoffs between leg length,
waterline area, speed, wave response, and stabilizer effectiveness.  We will tay with the 
size and weight of the above, and the 3 legs.   

We want a table that show what different length/width legs do to stability, cost, and speed.  
And that smaller waterline makes the seastead move less so there is less motion for the stabilizer to get rid of.

It should take into account that the stabilizer works better when going faster.
The force the stabilizer produces depends on the size and the speed.  Then sort of convert
this to feet of stability influence by taking how many feet (or part of a foot) that much force is
for the waterline area and 64 lbs/cubic-ft of seawater.


Please make an interactive html spreadsheet where I can set the values for:
  
Electric Pow to RIMs (Watts - default 10,000)
RIM Efficiency (% - default 40%)
Wave Peak-to-Trough(ft)   (default 5)
Wave Period (s)      (default 5)
Stabilizer wingspang  (ft)  (default 10)
Stabilizer chord  (ft)      (default 1)
Stabilizer Lift Coefficient (CL)  (default 1)


Then for these 3 Leg profiles:
Leg Profile 	Dimensions (Total L, Draft, Chord, Width) 	
   NACA 0040               (keep 10 foot chord and calculate with same volume))
   NACA 0030                 39,  19.5,  10,  3    (baseline)
   NACA 0025               (keep 10 foot chord and calculate with same volume)

I want a simplified model/calculation for wave response.  Lets assume we are stationary to start and just look at the top half of the wave.
So for a 5 foot wave just the water going up an extra 2.5 feet over that part of the wave period (about 1/4th of the total wave period).
Then after we know how much the leg would move without the stabilizer can subtract out what the stabilizer can remove and get a net motion.
So in the 2.5 feet of wave maybe the leg without stabilizer goes up 1.5 feet and the stabilizer subtracts 0.5 feet for a net movement of 1 foot.
The Column headers in the table should be something like the following info:


Waterplane Area (Total Sq Ft) 	

Restoring Force (Lbs per ft water height ) 	

Est. Speed useing  10kW power (Knots) 	

Heave without stabilizer in ft for 5 foot wave (in ft)

Stab Force   (Total Lbs) 	

Stab Influence (Ft Equivalent) 	

Heave WITH Stabizer included, (Final Motion)

Estimated weight of each leg in Marine Aluminum

Estimated cost of 1 leg and 1 stabilizer in Marine Aluminum