MVP Seastead Design

Containerizable Trimaran Platform — Minimal Viable Product for Caribbean Deployment

Fits in tagline>Derived from full design at seastead.ai — Scaled for 45' High Cube Container

Executive Summary

This MVP reduces the full 44 ft triangle design to a 36 ft equilateral triangle while preserving all core stability, redundancy, and containerization advantages. The smaller footprint creates margin in the 44.6 ft container for easier loading, adds structural safety factor, and reduces displacement requirements — while still delivering superior stability vs. monohulls and full liveaboard capability for 2.

Container: 45' High Cube (7.7' W × 8.9' H × 44.6' L) — 62,000 lbs max payload
Platform: 36 ft triangle, 7 ft headroom, 3 × 18.5 ft NACA 0035 foil legs
Displacement: ~22,000 lbs at design waterline (80% of container weight budget)
Stability: SWATH-like — 1 ft waterline change ≈ 1/6 buoyancy (vs 1/7 full scale)
Power: Triple-redundant LiFePO4 (25% displacement), 6 × RIM drives, full solar roof
Systems: Watermaker, fridge/freezer, sleeping for 2, storage, HVAC-ready

Container Packing Plan

All components pack into one 45' High Cube container with ~15% volume margin and ~20% weight margin.

Layout (Top View)

CONTAINER: 44.6 ft L × 7.7 ft W × 8.9 ft H ┌─────────────────────────────────────────────────────────────┐ │ ▲ ▲ ▲ ████████ ████████ ████████ ████████ ████████ │ ← Left wall: 3 wall panels upright (7' H × ~10" W each = 2.5' W) │ │ │ │ █ LEG █ █ LEG █ █ LEG █ █ SYS █ █ SYS █ │ Center: Systems crates, floor/ceiling panels, dinghy box │ ▼ ▼ ▼ ████████ ████████ ████████ ████████ ████████ │ │ │ │ ◄────────── 36 ft ─────────► ◄─── 8.6 ft ───► │ ← 36 ft triangle sides fit with 8.6 ft margin │ │ │ Right wall (2.5 ft wide): │ │ ┌─────────────────────────────────────────────────────────┐│ │ │ LEG 1 (round down) + LEG 2 (round up) STACKED ││ → 2 legs nested, chord-to-chord = ~16" thick │ │ LEG 3 (round down) — along door opening ││ → 3rd leg forward of stack │ └─────────────────────────────────────────────────────────┘│ └─────────────────────────────────────────────────────────────┘

Packing Details

Item	Qty	Orientation	Container Space	Weight (lbs)
Wall Panels (3 × 36' × 7' × 10")	3	Upright, left wall	2.5' W × 7' H × 36' L	3,600
Foil Legs (18.5' × 8.5' chord × 16" thick)	3	2 nested + 1 solo, right wall	2.5' W × 8.9' H × 19' L	6,000
Mid-triangle Beams (22' × 3)	3	Flat, center floor	1' W × 22' L	900
Floor/Ceiling Panels (bolt-in)	~12	Flat stacked	2' W × 4' H × 10' L	2,400
Walkway/Railing Kit (prefab sections)	1 set	Flat packed	1.5' W × 2' H × 12' L	800
RIM Drives (1.5' dia)	6	In leg crates	In leg volume	1,200
Battery Modules (LiFePO4, 25% disp)	3 banks	Pre-installed in legs	In leg volume	4,400
Electronics/Inverters/Controllers	3 sets	In leg crates	In leg volume	600
Solar Panels (roof, flexible)	~3.5 kW	Rolled, center	1' W × 1' H × 15' L	400
Watermaker + Fridge + HVAC	1 each	Crated, center	2' W × 2' H × 4' L	500
Dinghy (14' RIB deflated) + Outboard	1	Boxed, center	3' W × 2' H × 5' L	350
Mooring Screws (3 pairs) + Motors	3 sets	Crated, center	2' W × 1.5' H × 6' L	600
Hardware/Fittings/Tools/Spares	1 lot	Crated	2' W × 2' H × 4' L	800
TOTAL			~85% volume	~22,550 lbs

Hull & Leg Design (MVP Scaled)

Foil Legs — NACA 0035

Chord	8.5 ft (trimmed 0.5' at TE → 8.0' effective)
Span (Length)	18.5 ft (vs 21.5' full scale)
Max Thickness	2.975 ft (35% chord)
Draft (50% submerged)	9.25 ft
Freeboard (leg top to WL)	9.25 ft
Waterline Area (per leg)	~42 ft² (8.5' × ~5' wetted chord at midspan)
Buoyancy per Leg	~7,300 lbs (fresh) / ~7,500 lbs (salt)
Total Displacement	~22,500 lbs
Reserve Buoyancy (above WL)	~22,500 lbs (100% reserve)

Structural Integration

Each leg attaches at triangle vertex via 3-bolt flange pattern (12" bolt circle) — allows ±2° alignment adjustment
Leg center at thickest point sits 1.5 ft inside triangle vertex — maximizes lever arm while keeping attachment in panel area
Legs parallel, leading edges forward — Cd ≈ 0.04 vs ~1.0 for cylinders
Top 9.25' of each leg has integral aluminum ladder rungs (every 12") on forward face
4 heave plates per leg (bolt-on, 4' × 4' × 0.5") at 25%, 50%, 75% draft — tune heave natural period to >12s
Each leg: 6 watertight compartments (bulkheads every 3') — flood any 2, remain afloat

Superstructure — Living Triangle

Frame & Envelope


Triangle Side	36 ft (equilateral)
Wall Height	7 ft (floor to ceiling)
Wall Construction	Sandwich: 3mm Al skins + 4" PVC foam core (R-18)
Wall Width	10" (structural + insulation + conduit chase)
Floor/Ceiling	12" deep truss panels, bolted to mid-triangle beams
Mid-Triangle Beams	3 × 22 ft, connect wall midpoints at floor & ceiling
Max Panel Span	22 ft (mid-triangle) → all other spans < 22 ft
Doors	2 on back wall: 2' from each corner, 36" × 80"