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.








I am thinking to have a dingy,  a tender, and a canister liferaft.
Probably they only have to hold 4 or 6 people.
We are only going to be in the Caribbean and not in the hurricane season.

I think the Chinese boats have very good prices.

For the dingy I am thinking 14 foot (some places get bothered if your dingy is larger) with a 
Yamaha Harmo electric motor.   We can charge the dingy battery from the seastead solar so
not have to worry about running out of fuel for this.

It would also be good to have a tender that was bigger and could go 
further and faster and handle the open ocean better.

In Anguilla most people think a boat going into the open ocean should have two engines,
in case one breaks.   So two smaller outboards on the tender seems better than one large one.

If we are still 10 miles from an island and the weather is nice some people might hop
into the tender and go ahead to visit the island when the seastead was still going to
take another 10 hours at 1 MPH to get there.

Or of someone needed medical attention, something faster would be good to have.

If there was a storm coming that the seastead could not move fast enough to avoid we could 
get into this tender/lifeboat and head to some safe location.   Then the seastead
could be controlled remotely and hopefully make it through the storm and then we go 
back to it.

So the tender has somewhat of a survival function as well.  

Now we are hoping to have the whole seastead sell for maybe $500,000 or $600,000 so 
we are trying to keep costs down.

What would you recommend as far as:
   1) dingy 
   2) tender
   3) liferaft

Please explain the choices, give costs, weights, speeds, and links.