Based on provided specifications for a trimaran-style seastead with three NACA foil-shaped floats.
| Parameter | Estimate | Notes |
|---|---|---|
| Total roof area (triangle) | ~1,600 sq ft | 80ft x 40ft x 0.5 |
| Usable solar area (after obstructions) | ~1,200 sq ft | ~75% coverage |
| Solar panel wattage (modern marine) | ~200 W per 17 sq ft | ≈11.8 W/sq ft |
| Total installed solar watts | 14,160 W | 1,200 sq ft × 11.8 W/sq ft |
| Average Caribbean sun hours/day | 5.5 equivalent peak hours | Accounting for clouds, angle, losses |
| Average daily solar production | 77.9 kWh/day | 14.16 kW × 5.5 h |
| Battery capacity | 500 kWh LiFePO4 | |
| Battery weight | ~11,000 lbs (5,000 kg) | ~22 lbs/kWh typical for LiFePO4 |
| Battery cost | $45,000 | 500 kWh × $90/kWh |
| 24-hour average continuous power (from daily solar) | 3,246 W | 77,900 Wh ÷ 24 h |
| Component | Watts (avg) | Hours/day | Wh/day |
|---|---|---|---|
| Air Conditioning (1 unit cycling) | 1,200 | 12 | 14,400 |
| Watermakers (2 total, intermittent) | 800 | 4 | 3,200 |
| Refrigeration | 200 | 24 | 4,800 |
| Lighting, electronics, misc | 500 | 10 | 5,000 |
| Starlink (2 units) | 150 | 24 | 3,600 |
| Total house loads | 2,850 W avg | 31,000 Wh/day |
Extra solar power available: 77.9 kWh produced - 31 kWh used = 46.9 kWh/day for propulsion.
Percent extra solar: ~151% extra (46.9 / 31 × 100).
Using 46.9 kWh/day for propulsion continuously (24h):
Average propulsion power = 46,900 Wh ÷ 24 h = 1,954 W.
With 6 rim-drive thrusters (estimated 50-60% efficiency), this could sustain approximately 3-4 knots in calm conditions.
Note: Drag increases with cube of speed; higher speeds require disproportionately more power.
Estimated frontal area (with wind from front): ~600 sq ft (triangle frame + partial hull).
| Wind Speed | Drag Force (lbf) | Power to Hold Station (W) |
|---|---|---|
| 30 mph | ~900 | ~3,600 |
| 40 mph | ~1,600 | ~6,400 |
| 50 mph | ~2,500 | ~10,000 |
Assumptions: Cd ≈ 1.2, air density 0.00238 slugs/ft³, thruster efficiency ~50%.
With wings acting as daggerboards, the seastead could likely maintain control in winds up to 40-50 mph by generating hydrodynamic lift to counteract drift.
Starting with 500 kWh, subtracting 31 kWh/day for house loads leaves 469 kWh for propulsion.
| Speed (knots) | Power Required (W)* | Hours Endurance | Statute Miles | With Stabilizers? |
|---|---|---|---|---|
| 4 | 1,800 | 260 | 1,196 | On |
| 4 | 2,000 | 234 | 1,076 | Off |
| 5 | 3,500 | 134 | 771 | On |
| 5 | 3,900 | 120 | 690 | Off |
| 6 | 6,000 | 78 | 540 | On |
| 6 | 6,700 | 70 | 484 | Off |
| 7 | 9,500 | 49 | 396 | On |
| 7 | 10,600 | 44 | 356 | Off |
| 8 | 14,000 | 33 | 305 | On |
| 8 | 15,600 | 30 | 276 | Off |
*Power estimates based on hull drag approximations for SWATH-like vessel.
| Item | Weight (lbs) | Cost (USD) | Notes |
|---|---|---|---|
| 1) Legs (3 ea, NACA foil) | 18,000 | $180,000 | Aluminum, welding, finish |
| 2) Body (triangle frame) | 22,000 | $220,000 | Including floor, roof, railings |
| 4) 6 RIM drive thrusters | 3,000 | $150,000 | $25k each typical |
| 6) Solar panels | 2,400 | $28,320 | $2/W for marine panels |
| 7) Charge controllers | 300 | $7,500 | MPPT, 3 systems |
| 8) Batteries (500 kWh) | 11,000 | $45,000 | LiFePO4 |
| 9) Inverters | 600 | $15,000 | 3× 10kW marine |
| 10) Watermakers & tanks | 1,200 | $20,000 | 2× 40GPH, 200 gal storage |
| 11) Air conditioning | 800 | $12,000 | 3× marine units |
| 12) Insulation | 1,500 | $10,000 | Closed-cell foam |
| 13) Interior fit-out | 5,000 | $80,000 | Kitchen, bath, furniture |
| 14) Waste tanks | 800 | $6,000 | Holding tanks, plumbing |
| 15) Glass & doors | 2,000 | $25,000 | Marine windows, sliding doors |
| 16) Refrigerator | 200 | $2,500 | Marine unit |
| 17) Davit/crane | 500 | $8,000 | 6-foot swing, electric |
| 18) Safety equipment | 1,000 | $15,000 | Life rafts, EPIRB, flares, etc. |
| 19) Dinghy (14ft RIB) | 800 | $25,000 | With outboard |
| 20) Sea anchors | 300 | $3,000 | 2 large |
| 21) Kite propulsion | 200 | $10,000 | 20× 6ft stacked kites |
| 22) Air bags (safety) | 1,600 | $12,000 | 8 per leg |
| 23) Starlink (2×) | 20 | $1,200 | Dishy + router |
| 24) Trash compactor | 150 | $1,500 | |
| 25) Stabilizers (3×) | 900 | $30,000 | Aluminum, actuators |
| 26) Contingency/misc | 5,000 | $50,000 | Paint, wiring, fasteners, etc. |
| TOTALS | 79,270 lbs | $937,020 |
Note: Costs exclude design, engineering, shipping to assembly site, and assembly labor.
Natural Roll Period (side-to-side): ~6-8 seconds (due to wide weight distribution).
Natural Pitch Period (front-back): ~4-6 seconds.
Damping: The three hulls provide good damping; likely 5-10% of critical damping.
| Wave Condition | Direction | Stabilizers | Tip (ft) | G-force |
|---|---|---|---|---|
| 3ft, 3sec | Front | On | 0.5 | 0.02 |
| 3ft, 3sec | Side | On | 0.3 | 0.01 |
| 5ft, 5sec | Front | On | 1.2 | 0.05 |
| 5ft, 5sec | Side | On | 0.8 | 0.03 |
| 7ft, 7sec | Front | On | 2.5 | 0.12 |
| 7ft, 7sec | Side | On | 1.5 | 0.07 |
| With stabilizers off, expect ~30-50% larger motions. | ||||
Comparable living area (~1,200 sq ft) would require a ~80-90ft catamaran.
Cost comparison: A new 80-90ft catamaran typically costs $2.5-4 million.
This seastead would cost approximately 25-40% of a comparable catamaran.
Stability: The seastead's SWATH-like design with widely spaced hulls should have significantly less pitch and roll in 7ft waves than a 100ft catamaran.
Registering as a "trimaran yacht" in Panama/Liberia would be possible but challenging. Key issues:
Recommendation: Engage maritime attorney early in process.
| Metric | Value |
|---|---|
| Estimated cost (first unit) | $937,020 + design/assembly (~$1.2-1.5M total) |
| Cost each (20 units) | ~$850,000 each (economies of scale) |
| Average solar produced | 77.9 kWh/day |
| Average solar used (house) | 31 kWh/day |
| Average power for propulsion | 46.9 kWh/day (1,954 W continuous) |
| Buoyancy for customers/gear | ~15,000 lbs reserve buoyancy |
| 24/7 cruising speed (Caribbean) | 3-4 knots (calm conditions) |
Important Disclaimers: These are rough estimates based on general engineering principles and typical component costs. Actual performance would require detailed naval architecture analysis, CFD modeling, and professional engineering. Costs are approximate and will vary based on final specifications, material prices, and assembly location.