This seastead combines several well-understood marine engineering ideas — small-waterplane-area hulls, trimaran stability, foil-shaped legs, servo-tab stabilizers, and tension-leg mooring — into a single design that ships flat in a standard 45-foot High Cube container. The result is a light, comfortable, energy-self-sufficient floating home that can move under its own power, sail with a kite, anchor rock-steady, and connect with other units to form a community.
The three buoyancy legs are placed at the corners of a 44-foot equilateral triangle. That is an extremely wide stance for a vessel of this size. With buoyancy spread that far from the center, the righting moment is enormous and the seastead is effectively impossible to capsize. Unlike a monohull, which depends on ballast and hull shape for stability, this design gets its stability from pure geometry — the same principle that makes offshore oil platforms and large trimarans so secure.
Because each leg has a relatively small cross-section at the waterline, the seastead does not feel every passing wave. Wave forces are roughly proportional to the area of hull intersecting the water surface, so a small waterplane area means small heave and pitch forces. This is the same principle used by SWATH (Small Waterplane Area Twin Hull) vessels and semi-submersible platforms, which are known for being remarkably comfortable even in rough seas. Small waves are largely ignored; the seastead simply doesn't notice them.
A pure small-waterplane design can be in trouble if waves are large enough to submerge the hulls. This design avoids that problem because each leg is 14.5 feet long with only the bottom half normally in the water. As waves grow larger, more of the leg enters the water, providing strong reserve buoyancy that lifts the seastead up and over big swells. So the design ignores small waves but rides over big ones — the best of both worlds.
Each leg uses a NACA 0030 airfoil section with the rounded leading edge facing forward. This gives two big advantages over the typical cylindrical columns of a semi-submersible:
Because buoyancy is concentrated in three slender legs rather than a full hull, the structural weight required for a given amount of floor area is far less than a conventional boat of equivalent size. Boat cost scales strongly with displacement, so a lighter boat for the same living space is a dramatically cheaper boat.
The roof of a 44-foot equilateral triangle is roughly 838 square feet — almost entirely usable for solar panels. Because the underlying structure is light, the ratio of solar generation capacity to total displacement is excellent. This makes year-round, off-grid electric operation practical, including running the thrusters for propulsion.
Roughly 25% of the displacement is LiFePO4 batteries, and they live at the bottom of the three legs — deep underwater and far from the center of the vessel. This:
Each of the three legs has a small "airplane-shaped" stabilizer near its base. Active stabilization works especially well here for two reasons:
The stabilizers use a servo-tab arrangement: a small actuator moves only the elevator on the tail, which then changes the angle of attack of the much larger main wing. This lets a large stabilizer fin be driven by a tiny, cheap, low-power actuator — a huge cost and reliability advantage.
Each leg has its own batteries, charge controller, and inverter. The thrusters and stabilizer on each leg run off that leg's electrical system. If any one system fails, the other two continue to provide propulsion, stabilization, and power. There are no single points of failure in the power architecture.
The legs have no through-hull penetrations. Electrical wiring to the thrusters and stabilizers runs through a conduit welded to the trailing edge of each foil. Each leg is also divided into multiple airtight compartments, so a single leak cannot flood a leg, let alone the vessel. This is a much safer arrangement than typical boats with many through-hull fittings.
For extended stays in one place, three helical screw anchors can be set into the seabed and the seastead pulled down slightly against its own buoyancy with tension legs. Because the legs have small waterplane area, the buoyancy force changes very little with tide, so the tension stays nearly constant. The result is an anchored platform that hardly moves at all — ideal for digital nomads who want to work comfortably at anchor.
Every major component is sized to fit into a single 45-foot High Cube container:
This makes worldwide shipping cheap and simple, and lets the seastead be manufactured in a low-cost, highly-automated facility (in China) and delivered anywhere with a port.
A track around the top of the walls lets a kite-flying device move freely around the perimeter, automatically following the optimum angle to the wind. Because the foil-shaped legs resist sideways drift like daggerboards, the seastead can actually make way under kite power. In a storm, the same foils provide directional control while running before the weather under a drogue.
Two seasteads can be joined back-to-front by a walkway. While underway, the onboard computers of both vessels coordinate their thrusters and stabilizers to minimize relative motion of the walkway — especially when a person is about to cross. This turns isolated platforms into a real community where people can move freely between homes.
Each of the three corners has a covered outdoor deck with railings and a door into the living area. A 3-foot walkway with railing wraps around most of the exterior, connecting the corner decks. At the back, two extended decks flank the dinghy, which hangs sideways and is sheltered from headwinds by the living-area wall when underway.
Each of these features is good on its own, but the combination is what makes the design exceptional:
And all of this is before any of the optional extras are added.