Analysis of adding photovoltaic panels to the vertical walls of the triangular living area (44 ft sides, 7 ft high walls with a 3 ft exterior walkway). The walkway sits 1 ft above the wall bottom, leaving 6 ft of vertical wall above the walkway for panel mounting.
Adding solar to the three vertical walls could yield ~32 kWh/day (AC) in the Caribbean, increasing total solar harvest by ~60% over roof-only. Estimated added cost: $12,000–$15,000; added weight: 1,500–2,400 lbs (using marine-grade semi-flexible panels). This is likely worthwhile if energy demand is high (propulsion, HVAC, living loads) and the structure can accommodate the weight. Main risks: salt-spray degradation, wave impact, and added windage.
| Parameter | Value | Notes |
|---|---|---|
| Location | Caribbean (~20° N latitude) | Low seasonal variation, high sun angles |
| Wall dimensions | 3 × 44 ft × 6 ft (above walkway) | Total gross area = 792 ft² |
| Doors (back side) | 2 × 3 ft × 6 ft | Reduce net area by 36 ft² |
| Net mountable area | 756 ft² (70.2 m²) | |
| Panel coverage factor | 80 % | Allowance for framing, wiring, walkway brackets |
| Effective panel area | 56 m² (605 ft²) | |
| Panel type | Marine semi-flexible (e.g., SunPower Maxeon or similar) | Better impact resistance, lighter than glass |
| Panel efficiency | 20 % | Conservative for modern semi-flexible |
| Panel weight | 2.5 lb/ft² (12.2 kg/m²) | Includes adhesive/mounting backing |
| Installed cost | $1.50–$1.80/W (DC) | Marine-grade, includes waterproof connectors, conduit, labor |
| System losses (DC→AC) | 20 % | Charge controller, inverter, wiring, temperature |
| Ocean albedo (effective) | 0.10 | Diffuse + specular reflection for vertical surface |
| View factor to water | 0.5 | Vertical wall sees half hemisphere as water |
The equilateral triangle can be oriented with one side facing true south (optimal for northern hemisphere). The other two sides then face 60° (ENE) and 300° (WNW). Using typical clear-sky models for 20° N latitude, the average daily plane-of-array (POA) insolation for each orientation is estimated below. Albedo contribution is added as 0.5 × albedo × GHI (GHI ≈ 5.5 kWh/m²/day).
| Wall Orientation | Azimuth (° from N) | Direct + Diffuse POA (kWh/m²/day) | Albedo Gain (kWh/m²/day) | Total POA (kWh/m²/day) |
|---|---|---|---|---|
| South-facing (side 1) | 180 | 4.2 | 0.28 | 4.48 |
| ENE-facing (side 2) | 60 | 3.0 | 0.28 | 3.28 |
| WNW-facing (side 3) | 300 | 3.0 | 0.28 | 3.28 |
| Area-weighted average | 3.4 | 0.28 | 3.68 |
Note: If the seastead cannot maintain a fixed heading, the average over all rotations is ~3.2 kWh/m²/day (direct+diffuse) + 0.28 albedo = 3.48 kWh/m²/day. The oriented case is used for the main estimate.
| Step | Calculation | Result |
|---|---|---|
| Effective panel area | 56 m² | |
| DC energy per m² per day | 3.68 kWh/m²/day × 20 % | 0.736 kWh/m²/day |
| Total DC energy per day | 56 m² × 0.736 kWh/m²/day | 41.2 kWh/day |
| AC energy after losses (20 %) | 41.2 × 0.8 | 33.0 kWh/day |
| Annual AC energy | 33.0 × 365 | 12,045 kWh/year |
| Item | Low Estimate | High Estimate | Notes |
|---|---|---|---|
| DC capacity | 8.4 kW | 8.4 kW | 56 m² × 150 W/m² |
| Panel + mounting hardware cost | $12,600 | $15,120 | $1.50–$1.80/W |
| Wiring, connectors, conduit | $1,500 | $2,500 | Marine-grade, 3 separate circuits to leg inverters |
| Engineering & installation labor | $2,000 | $4,000 | Depends on shipyard |
| Total installed cost | $16,100 | $21,620 | |
| Panel weight | 1 |