80-ft triangular aluminum trimaran-form platform • living area, solar, 6 rim-drive thrusters • Caribbean operations
| Item | Value | How |
|---|---|---|
| Area inside 80-ft equilateral triangle | 2,771 ft² = 0.064 acre | (√3/4)·80² = 2,771 |
| Rectangle length (14 ft wide, nose as far forward as possible, tail on “back” edge) | ≈ 57.2 ft | Top corners touch the slanted sides: apex offset = 7/tan30° = 12.1 ft; length = 69.28 − 12.12 = 57.16 ft |
| Living area floor area | ≈ 800 ft² | 14 × 57.16 |
| Living area volume (8 ft walls) | ≈ 6,400 ft³ | 800 × 8 |
| Open netting area (triangle minus rectangle) | ≈ 1,970 ft² | 2,771 − 800 |
| Solar roof usable | ≈ 800 ft² | Full roof minus hatches/walkway |
| Fold-down side panels (both sides, 8 ft out) | ≈ 912 ft² | 2 × (57 × 8) |
Each leg is treated as a streamlined foil filling ~60% of its 19 × 10 × 4 ft bounding box → ~455 ft³ full volume. At the 50% waterline each leg displaces ~228 ft³ ≈ 14,600 lb; three legs ≈ 43,800 lb total buoyancy at design waterline. The 24 air bags (below) add ~6,000 lb of emergency reserve.
| Load group | Weight (lb) |
|---|---|
| Structure (frame, body, netting, legs) — aluminum build | 16,100 |
| All equipment & outfit (see §8) | 14,340 |
| Water in tanks (400 gal) + outboard fuel | 3,465 |
| Boat ready-for-guests | 33,900 |
| Remaining buoyancy for guests + personal gear | ≈ 9,900 |
| Criterion | Duplex SS 2205 | Marine Aluminum (5083/6082) |
|---|---|---|
| Density | 7.8 g/cm³ | 2.7 g/cm³ (2.9× lighter per volume) |
| Structure weight (same stiffness) | ~31,000 lb | ~16,100 lb |
| Structure cost (China fab) | ~$260–280k | ~$103k |
| Corrosion life, tropical seawater | 50+ yrs (PREN ≈ 34; superb pitting/crevice resistance; still wants anodes) | 30–40+ yrs with coatings, anodes, washdowns (proven in fast ferries) |
| Fabrication notes | Skilled welding w/ nitrogen backing; heat-input control; hard to repair in remote yards | Easy MIG/TIG; any yard can repair; fatigue-friendly |
| Payload impact | −15,000 lb → erases guest/payload margin | Keeps ~10,000 lb margin |
| Flow | kWh/day | Avg watts |
|---|---|---|
| Solar produced (typical day) | ≈ 135 | 5,600 W |
| Household use, no propulsion (AC 6, cooking 2, fridge 1.5, watermaker 0.8, Starlink/electronics 1.2, lights 0.5, pumps/misc 1, laundry ~1) | ≈ 15 | 625 W |
| Surplus available for propulsion | ≈ 120 (≈ 89% of harvest) | 5,000 W |
Head-on drag area CdA ≈ 220 ft² (cabin end 112 ft² + legs/frame/panels ~110 ft², Cd≈1.0). Force F = 0.00256 · V² · CdA (lb, mph). Thruster power ≈ 0.5 · F · vexit, vexit ≈ 3 m/s (≈ 6.7 W per lb of thrust).
| Wind | Force (lb) | Force (kgf) | Hold-station power |
|---|---|---|---|
| 30 mph | ≈ 500 | ≈ 230 | ≈ 3.4 kW |
| 40 mph | ≈ 900 | ≈ 410 | ≈ 6.0 kW |
| 50 mph | ≈ 1,400 | ≈ 640 | ≈ 9.4 kW |
All comfortably within the 30 kW thruster installation — you can hold station in 50 mph indefinitely on solar+battery.
In this mode the wind load on the cabin/frame becomes mostly a sideways force. The three deeply-immersed wings (huge lateral area, like a sailing trimaran’s boards) convert it to leeway resistance rather than downwind drift. The thrusters only need to supply the small residual fore-aft component — effectively the platform “sails” on its own windage with propeller drive. Estimated control authority: sustained control to ~45–50 knots with sea room; beyond that, deploy sea anchors and bow-in as in §5 above. Caveats: verify rudder/thruster steering authority and wing root bending loads at 50+ kt in the design phase.
Method: λ = gT²/2π; max height difference over span d = H·sin(πd/λ), scaled by a dynamic response factor (short waves are filtered by the 80-ft beam and distributed mass; long waves are followed more closely). Vertical accel a = (2π/T)²·(H/2)·response. These are worst-case amplitudes, not averages.
| Wave | Head seas (wave from front) | Beam seas (wave from side) | ||
|---|---|---|---|---|
| Front-vs-back tip (Δh over 57 ft) | G at center | Side-vs-side tip (Δh over 14 ft) | G at center | |
| 3 ft @ 3 s | ≈ 1–2 ft (pitch ≈ 1–2°) | ≈ 0.10 g | ≈ 1.0 ft (roll ≈ 4°) | ≈ 0.10 g |
| 5 ft @ 5 s | ≈ 3.5 ft (pitch ≈ 3.5°) | ≈ 0.09 g | ≈ 1.2 ft (roll ≈ 5°) | ≈ 0.09 g |
| 7 ft @ 7 s | ≈ 3.5–4.5 ft (pitch ≈ 4°) | ≈ 0.07 g | ≈ 1.0 ft (roll ≈ 4°) | ≈ 0.08 g |
Wetted surface ≈ 3 legs × ~220 ft² ≈ 660 ft². Resistance ≈ 122·v² (N, v in m/s) including form/wave-making allowance. Average propulsion power 5.0 kW at 55% propulsor efficiency → 2,750 W at the hull:
Steady 24/7 speed ≈ 2.8 m/s ≈ 5.5 knots ≈ 6.3 mph → ~145–150 miles/day, every day, on sunlight alone.
Sprint (all 30 kW): ~8–9 mph briefly. With the kite train flying in 15–20 kt trades, add 0.5–1.5 mph.
| # | Item | Weight (lb) | Cost (USD) | Notes |
|---|---|---|---|---|
| 1 | Legs ×3 (buoyancy foils) | 4,200 | 30,000 | 5083 plate ~5 mm + framing; bulkheads recommended |
| 2a | Living-area structure (floor/walls/roof) | 7,000 | 45,000 | ~2,700 ft² envelope |
| 2b | Triangle truss / 4-ft railing (240 ft run) | 4,500 | 25,000 | Tube truss, doubles as guardrail |
| 2c | Netting + steps | 400 | 3,000 | Catamaran-style trampoline |
| 4 | Rim-drive thrusters ×6 | 450 | 24,000 | 5 kW each, 48 V, ~$4k each |
| 6 | Solar panels + mounting | 2,650 | 28,000 | 14.3 kW rigid roof + 20 kW flex fold-downs, hinges, wiring |
| 7 | MPPT charge controllers | 300 | 10,000 | ~700 A total at 48 V, split across 3 trains |
| 8 | LiFePO₄ batteries (34 kWh) | 700 | 11,000 | ~235 lb per float; expandable |
| 9 | Inverter/chargers ×3 (5 kW) | 360 | 8,000 | Victron-class |
| 10 | Watermakers ×2 + 400 gal tankage | 350 | 12,000 | Tanks empty-weight; water counted in §2 |
| 11 | Air conditioning ×3 (12k BTU inverter) | 250 | 5,000 | Run one at a time |
| 12 | Insulation (2″ PU, full envelope) | 900 | 8,000 | Critical in tropics — don’t skimp |
| 13 | Interior: flooring, cabinets, kitchen, furniture, baths, bedroom | 3,500 | 40,000 | Lightweight marine joinery |
| 14 | Waste tanks (black/gray ~150 gal) | 150 | 2,000 | + deck pump-out fitting |
| 15 | Glass & glass doors (ends + sidelights) | 1,500 | 12,000 | Laminated, storm-rated |
| 16 | Refrigerator/freezer (48 V DC) | 250 | 2,000 | |
| 17 | Biofouling gain, year 1 | ~1,000 | — | Slime/weed/barnacles on ~660 ft² wetted + nets; variable 300–2,500 lb; schedule diver cleans |
| 18 | Safety equipment | 400 | 8,000 | 8-man raft, EPIRB ×2, PFDs, flares, extinguishers, first aid |
| 19 | Dinghy: 14-ft RIB + 25 hp outboard | 450 | 12,000 | |
| 20 | Sea anchors ×2 (para-type) | 150 | 3,000 | Storm drogue capability |
| 21 | Kite train: 20 × 6-ft kites + lines | 100 | 4,000 | Backup propulsion / fun / boost |
| 22 | Air bags, 8 per leg (24) | 150 | 3,000 | ≈ +6,000 lb emergency buoyancy |
| 23 | Starlink ×2 | 30 | 5,000 | Flat-mount, auto failover |
| 24 | Trash compactor | 100 | 1,500 | Smart for offshore living |
| 25 | Davit/crane/winch for dinghy | 250 | 4,000 | 1,500 lb SWL |
| 26 | Everything else: anchors ×2 + rodes, nav electronics (plotter/AIS/VHF/autopilot), bilge pumps + alarms, fire suppression, lightning protection, anodes/coatings, fenders/lines, tools/spares, outboard fuel | 1,400 | 15,000 | The inevitable long tail |
| TOTALS (excl. water in tanks & guests) | ≈ 30,400 | ≈ 321,500 | ||
| Line | First unit | Qty 20 |
|---|---|---|
| Equipment + China fabrication (above) | $322k | $258k (−20% learning curve) |
| Ocean freight (~7 × 40′ containers) | $25k | $22k |
| Yard assembly, systems integration, testing | $80k | $56k |
| Engineering, design, certification amortized | $40k | $10k |
| Contingency | $55k | $35k |
| Finished, commissioned unit | ≈ $525k | ≈ $390k |
| Line | Per week |
|---|---|
| Charter rate (6 guests, all-inclusive w/ captain + chef; novel “floating villa” premium) | $15,000–20,000 |
| Crew (2) | −2,500 |
| Provisioning | −1,200 |
| Fuel, consumables | −400 |
| Maintenance reserve | −1,200 |
| Insurance (amortized) | −800 |
| Marketing / booking platform (~10%) | −1,600 |
| Fees, admin, misc | −700 |
| Expenses ≈ 50–55% → Cash profit | ≈ $7,000–9,500 |
Payback: $525k ÷ ~$8k ≈ 65 booked weeks — about 2 years at a realistic 30 booked weeks/year (ignoring capital cost/depreciation, per your framing). First-unit payback closer to 3 years; fleet units ~1.5–2 years.
Registering as a “trimaran yacht” is plausible — it literally has three hulls — but expect friction beyond a normal yacht:
Genuinely promising as a luxury-experience product: unmatched space-per-dollar, solar-native operation, novelty premium, and container-shippable. The business risk is not the hardware — it’s insurance, regulatory acceptance, and weather-exposed operations. Partner early with a charter-management firm and an insurer willing to engage at concept stage.
First product: dozens of units/year globally — ultra-luxury charters, floating villas for resorts, eco/research platforms, resilient housing demos. Plausibly a $10–30M/year segment initially, growing if insurance/regulatory paths mature. You are early; being early with a working, insured, chartered unit is itself the moat.
Reasonably safe, yes — with discipline. At ~6 mph 24/7 you can reposition 140+ nm/day. The deep-southern Caribbean (Curaçao/Bonaire/Guajira, ~12°N) is outside the main genesis/track corridor. By 2028, 5-day track errors should be ~150 nm — your daily mobility exceeds forecast uncertainty. Maintain a 72-hour decision loop, pre-briefed bolt holes (Curaçao, Bonaire), sea-anchor + bow-in protocol, and respect the June/October in-place formation risk. Never ride out a named storm at a mooring.
| System | Status |
|---|---|
| Propulsion (6 thrusters) | ✔ Redundant |
| Electrical (3 independent trains + ties) | ✔ Redundant |
| Comms (2× Starlink) | ✔ + add VHF/Iridium backup |
| Water (2 makers + 400 gal storage) | ✔ Redundant |
| Flotation breach (air bags) | ✔ + ADD bulkheads & bilge pumps/alarms |
| Fire in living area | ⚠ ADD suppression + smoke/CO detection |
| Leg-to-frame structural joint | ⚠ Over-design + inspect; this is THE critical detail |
| Medical evacuation | ⚠ Written plan + drills |
| Anchoring for destination stops | ⚠ ADD primary anchor gear (sea anchors ≠ parking brake) |
| # | Question | Answer |
|---|---|---|
| 1 | Total cost, first unit / at qty 20 | ≈ $525k / ≈ $390k each |
| 2 | Solar produced / used (non-propulsion) / left for propulsion | ≈ 135 kWh/day / ≈ 15 kWh/day / ≈ 120 kWh/day |
| 3 | Spare buoyancy for guests + personal gear | ≈ 10,000 lb |
| 4 | Average 24/7 speed in the Caribbean | ≈ 6 mph (5.5 kn, ~145 mi/day) |