Triad Mk.I Seastead
Containerized MVP / Aluminum Flat-Pack Design
This proposal optimizes your triangular SWATH concept for a single 40-ft container shipment while preserving the largest possible solar and living footprint. Every structural member is either short enough to slide into a standard ISO box or ships as a nested, robotically-cut flat-pack panel.
Design Philosophy: One 40-ft container, one seastead. The kit is robotically cut and welded at a Chinese shipyard, shipped flat to the Caribbean, and bolted/riveted together on a beach or calm-water assembly slip. No piece is longer than 20 ft or wider than 7.4 ft.
1. Overall Layout & Dimensions
| Primary Hull Form | Triangular aluminum space-truss living pod on three SWATH foil-legs |
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| Triangle Geometry | Isosceles — 34 ft stern beam, 40 ft port/starboard sides (front vertex) |
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| Triangle Height (deck) | 36.2 ft from stern to bow |
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| Headroom | 7.0 ft floor-to-ceiling internal truss height |
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| Total Indoor Floor Area | ~580 ft² (clear open plan inside truss ring) |
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| Rear Swim Decks | Two 5 ft × 10 ft grated platforms, port & starboard of dinghy |
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| Solar Roof Area | ~615 ft² usable (triangle minus small bow framing gap) |
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2. The SWATH Foil-Legs
Three identical leg-floats provide buoyancy and low-drag forward motion. They attach via heavy-duty corner nodes that ring the truss triangle, with the top of each leg extending slightly into the triangle volume for a clean load path.
- Profile: NACA 0030 (constant section)
- Span (length): 19 ft total — 9.5 ft submerged, 9.5 ft above design waterline
- Chord (fore-aft): 10 ft
- Max Thickness (port-starboard): 3.0 ft
- Direction: Blunt leading edge faces forward; thin trailing edge aft
- Ladder: Integrated rungs cast into the forward face of the above-water half
Containerization Trick: A 10-ft chord cannot ship as a monocoque shell. Each leg is broken into eight flat-pack skin panels (four per side) sized ~19 ft × 2.8 ft, plus nested ring-frames and a longitudinal spine. The panels stack like deck planks inside the container, and all curved nose/tail sections are pre-rolled by robot before packing.
3. Propulsion & Stabilization
RIM-Drive Thrusters
- Quantity: 6 (one port, one starboard on each leg)
- Diameter: 1.5 ft
- Mounting: Through-hull pods, 3 ft up from leg bottom (~6.5 ft below waterline)
- Orientation: Axis horizontal, thrusting fore/aft
- Total Power: ~30 kW electric continuous
- Cruise Speed: ~6 knots calm water; 4 knots in moderate swell
Servo-Tab Stabilizers
- Quantity: 3 (one on trailing edge of each leg)
- Main wing: 12 ft span × 1.5 ft chord
- Fuselage / pylon: 6 ft long, clipped to leg trailing edge
- Elevator (servo tab): 2 ft span × 0.5 ft chord, actuated by a small linear motor
- Action: Tab changes local pressure, forcing main wing to ride at desired angle without a large main actuator
- Wings detach for shipping and ship inside the triangle frame cavity
4. Energy Budget
| Photovoltaic Array | ~8,000 W (e.g. 20× high-efficiency 400 W rigid panels, or lighter flexible walk-ons) |
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| Typical Daily Yield | 30 – 45 kWh (Caribbean average, depending on season & shading) |
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| Battery Bank (recommended) | 20 kWh LiFePO₄ (~200 kg / 440 lb) |
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| Battery Upgrade Headroom | Payload budget allows up to ~50 kWh before you trade living cargo |
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| Dinghy Power | Yamaha HARMO electric outboard on 14-ft RIB; charges from house bus |
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5. Container Packing Logic
The entire structural aluminum kit for one seastead fits in one 40-ft high-cube container (internal ~39.5 ft × 7.7 ft × 7.9 ft). Here is how the volume is used:
- Truss Modules (6 pieces): The triangle is built from six bolt-together space-frame modules. The longest single module is 20 ft × 2.5 ft × 7 ft. Three modules stand upright side-by-side (6 ft total width) and two rows of them occupy only ~20 ft of container length.
- Corner Nodes (3): Cast aluminum box nodes that join the truss and accept the leg spines. They nest inside the truss void.
- Leg Kits: Twenty-four pre-cut skin panels (~19 ft × 2.8 ft) stack flat in the remaining ~19 ft of length. Internal ring-frames and the leg spine slip between the stacks. Total packaged leg volume is roughly a 19 ft × 7 ft × 3 ft block.
- Decks & Stabilizers: Grated deck sections and the detached stabilizer wings slide into the remaining top/side gaps.
Result: One container, one seastead. A single flat-bed truck and standard crane can deliver the kit to any Caribbean launch site.
6. Displacement & Payload
| Submerged Volume (3 legs, 50% immersion) | ~590 ft³ |
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| Design Buoyancy (seawater) | ~37,500 lb / 17,000 kg |
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| Structural Aluminum Kit (lightship) | ~7,500 kg |
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| Solar, Drives, Glass, Systems | ~1,100 kg |
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| Recommended Battery | 200 kg |
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| Lightship + Outfitting | ~8,800 kg |
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| Remaining Payload (people, water, cargo, provisions, extra batteries) | ~4,200 kg (9,200 lb) |
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This gives you a comfortable safety margin. You could, for example, carry an additional 2,000 kg of batteries (20 kWh more) and still have two tonnes left for water, food, tools, and personal cargo.
7. Station-Keeping & Multi-Hull Community
- Anchor Mode: Three helical mooring screws are driven into the seabed by the dinghy or a diver. Synthetic tension legs run to eye-plates at the leg–truss nodes. Pre-tension draws the legs down so the platform barely heaves, behaving like a mini TLP.
- Two-Unit Connection: When moored, two Triads can raft stern-to-bow or side-by-side. A telescoping aluminum walkway (12 ft retracted, stored on the rear deck) extends and pins to the neighbor’s forward node. The matching truss geometry makes alignment simple.
- Underway in Pairs: For passage-making, a 50-ft tow line or magnetic fendering keep units close while a high-line trolley lets crew transfer if seas permit.
8. Manufacturing & Cost Estimate
Production assumptions: marine-grade 5083-H116 plate & 6061-T6 structural extrusions, robotic CNC cutting and robotic MIG/TIG welding at a mid-sized Chinese shipyard, with jigs and fixtures amortized across a 10-unit run.
Estimated Structural Kit Cost (10-unit run):
USD $58,000 – $68,000 per seastead
Likely settled cost: ~$62,000/unit at quantity 10.
| Raw Aluminum Material | ~8,000 kg / unit @ ~$6/kg |
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| Robotic Cutting & Rolling | Nesting software optimizing for flat-pack yield |
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| Robotic Welding + Fit-up Labor | ~30–40 hrs effective labor per kit |
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| Fixture & Programming Amortized | Spread across 10 units |
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| Surface Prep & Export Packing | Alodine + foam cradle pack for container |
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