We are working on a seastead design.
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 front to back and 40 feet wide.
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".

There will be a floor and roof/ceiling (7 foot inside) the full area of the triangle.
The enclosed living space will be 14 feet wide and 45 long on the centerline but one edge close to the back.
There covered area around the living space make an open porch.  
The living area will have lots of windows in the font and back and some along the side.    

There will be 3 floats/legs/wings that will be the buoyancy.
Each leg/wing will 19 feet long and have a NACA 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 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, one on each side of the legs/wings about 3 feet up from the bottom.
These will be aimed so they can push water past the wing and toward the back of the seastead.

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

Behind the living area will be two supports going over the railing and 2 ropes going down to a dinghy that
is a 14 foot RIB boat with 1 outboard motor that is sideways against the other side of the railing.   
When the seastead is moving the dingy will not feel the wind as the living area will block it.

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 4 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.








Now imagine that the top of the tailing on the port and starboard sides and curving around the front between them is 
has something like the top of an I-beam and that a little robot with 4 grooved wheels that can move along while flying 
a 2 string kite stack.  With proper control the kite can pull
off to the side of downwind.  If the robot moves toward the front of the seastead it can pull that more downwind,
and if it moves toward the back it can pull that part downwind, much like a windsurfer leaning the sail forward or backward to turn.
The 3 floats/legs/wings will act like 3 giant dagger-boards.  So if the robot can tack to gradually go upwind and
easily go to the side or downwind, like a sailboat.   This kite robot is completely independent of the
normal thruster method of control and propulsion, so it has independent failure modes and so would be a great 
backup propulsion system. 

We will have 3 electrical power systems and we could run an extension cord from any that was working
to the kite robot.  It might be fun though to have the robot have batteries that could charge from having the kite
pull it back and forth along the track (though this is more costly and complicated than a power cord). 

The kite will always fly on the downwind side of the seastead so the kite ropes will not go near the living area structure
but out over the open water side of the railing.

The track for the kite robot will curve around inside the point at the front of the seastead enough that there is room on the other side for a 
person.  The kites will really be "stack of kites" where the individual kites can be attached or detached quickly (maybe 20 to 50 kites).  
The robot will fly directly above while 
aiming the seastead downwind so there is minimal movement and pull from the kites when person attaching or detaching the kites.

If the kite stack is very powerful it will cause significant lean.  We could use the stabilizers to combat this and 
also limit the number of kites in the stack so the lean was acceptable.

Do RIM drives have a "spin freely" mode to reduce the drag from them?

What do you think of the kite idea?