Here is a ready‑to‑use HTML page that summarises the scaled dimensions, the water‑displaced weight (mass), and the rope lengths for both the 1/6‑scale model and the full‑size seastead.
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Seastead Scale Model – Froude Scaling Results
Seastead 1/6‑Scale Model – Froude Scaling
Froude scaling factor: 6 (linear).
All areas scale with 6² = 36, all volumes (and thus buoyant weight) scale with 6³ = 216.
1. Dimensions
| Component |
Model (1/6) |
Full Scale (×6) |
| Equilateral triangle side length |
10 ft |
60 ft |
| Leg (column/float) diameter |
5 in = 0.4167 ft |
30 in = 2.5 ft |
| Leg length (total) |
6 ft |
36 ft |
| Leg portion underwater (≈60 % of length) |
0.60 × 6 ft = 3.6 ft |
0.60 × 36 ft = 21.6 ft |
| Rope length (each of the two per leg) |
≈14.5 ft |
≈87 ft |
*Rope length is derived from the 45° leg geometry (see the calculation note below). The values are rounded to the nearest foot.
2. Buoyant Displacement (Water‑Displaced Weight)
Assumed water density: 62.4 lb/ft³ (fresh water). Using seawater (≈64 lb/ft³) would give ≈ 2 % higher numbers.
| Quantity |
Model |
Full Scale |
| Volume of one underwater leg |
π × (0.2083 ft)² × 3.6 ft ≈ 0.491 ft³ |
π × (1.25 ft)² × 21.6 ft ≈ 106 ft³ |
| Total underwater volume (3 legs) |
≈1.473 ft³ |
≈317.9 ft³ |
| Displaced weight (≈ mass) |
≈ 92 lb |
≈ 19 850 lb |
The target weight of the structure (including the triangle, legs, ropes, equipment, etc.) should equal the displaced weight shown above to achieve neutral buoyancy.
3. How the Numbers Were Obtained
- Linear scaling: Model dimensions multiplied by 6 give full‑scale values.
- Leg volume: Cylinder volume = π r² L. Only the underwater portion (60 % of the total length) contributes to buoyant lift.
- Rope length: Treat each leg as a 45° line from the corner of the triangle. The horizontal projection of the leg is L·cos45 = L·0.7071. Using the geometry of an equilateral triangle (side = 10 ft model / 60 ft full), the distance from the leg’s lower end to each adjacent corner works out to ≈ 14.5 ft (model) and ≈ 87 ft (full scale). Rope length scales linearly, so 14.5 ft × 6 ≈ 87 ft.
- Weight scaling: Because weight ∝ volume, the full‑scale weight = model weight × 6³ = 92 lb × 216 ≈ 19 850 lb.
4. Quick Reference Summary
- Triangle side: 10 ft (model) → 60 ft (full)
- Leg diameter: 5 in (model) → 2.5 ft (full)
- Leg length: 6 ft (model) → 36 ft (full)
- Leg underwater length: 3.6 ft (model) → 21.6 ft (full)
- Rope length (each): ≈ 14.5 ft (model) → ≈ 87 ft (full)
- Buoyant weight (displacement): ≈ 92 lb (model) → ≈ 19 850 lb (full)
Use these figures as a starting point for the detailed design of the full‑size seastead. Remember to add the weight of the triangle platform, any equipment, payload, and safety margins to the target displacement.
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