```html Seastead Design & Froude Scale Model Results

Seastead Design & 1/6 Scale Model Specifications

1. Mass of Water Displaced by Full‑Scale Legs

Each cylindrical leg (diameter = 3.9 ft, radius = 1.95 ft, length = 24 ft) is immersed two‑thirds (16 ft). With 3 legs, total immersed volume is:

V_immersed = 3 × π × (1.95 ft)² × 16 ft ≈ 573.5 ft³

Using sea‑water density ≈ 64 lb/ft³ (weight density), the weight of displaced water is:

Weight = 573.5 ft³ × 64 lb/ft³ ≈ 36,704 lb
Note: This is the buoyant force; the actual structure weight must be ≤ this value to float at the given immersion.

2. Froude‑Scaled 1/6 Model Dimensions

Froude scaling: all lengths are reduced by factor λ = 6. All dimensions below are for the model in inches.

Component Prototype 1/6 Model
Leg length (cylinder) 24 ft = 288 in 48 in
Leg diameter 3.9 ft = 46.8 in 7.8 in
Leg radius 1.95 ft = 23.4 in 3.9 in
Triangle frame side 60 ft = 720 in 120 in
Leg vertical projection (45°) 12√2 ft ≈ 16.97 ft = 203.6 in 33.9 in
Leg horizontal projection (45°) 12√2 ft ≈ 16.97 ft = 203.6 in 33.9 in

Cable Lengths (Model Scale)

Two cables run from the bottom of each leg to the two adjacent corners. One continuous cable loops between all three leg bottoms.

Cable Type Prototype Length 1/6 Model Length
Leg‑bottom to adjacent corner (each) ≈ 49.1 ft = 589 in ≈ 98.2 in
Loop cable (total) ≈ 91.8 ft = 1,102 in ≈ 183.6 in

3. Target Weight of Scale Model

Weight scales with volume (λ³). Prototype displaced‑water weight ≈ 36,704 lb.

Model weight = 36,704 lb ÷ 6³ = 36,704 lb ÷ 216 ≈ 170 lb
Verification from model dimensions: Model immersed volume = 3 × π × (0.325 ft)² × (8/3 ft) ≈ 2.65 ft³ → weight = 2.65 × 64 ≈ 170 lb.

4. Wave‑Height Scaling for Testing

Wave heights scale linearly with λ = 6.

Prototype Wave Height Model Wave Height (inches)
3 ft 6 in
5 ft 10 in
8 ft 16 in

5. Required Water Depth for Open‑Ocean Wave Conditions

To avoid shore‑breaking effects, the water should be deep enough that the wave speed is not influenced by the bottom. For deep‑water waves, depth should be > half the wavelength. A practical rule: depth should be at least 5–10 times the wave height.

For the largest model wave (16 in = 1.33 ft), a depth of ≈ 7 ft (model scale) is sufficient. In prototype terms, this corresponds to a depth of ≈ 42 ft, which is adequate for open‑ocean waves of 8 ft.

Recommendation: In Sandy Hill Bay, choose a location with at least 7 ft of water to ensure the model waves behave as deep‑water waves.

6. Android Apps for Acceleration Recording

These free Android apps record accelerometer data to a file (CSV) that can be exported to a computer:

All apps allow transfer via USB, email, or cloud storage.

Summary

```