Scale: 1:10 (Froude scaling laws applied)
| Parameter | Full Scale | 1/10th Scale Model |
|---|---|---|
| Triangle frame — side length (front to back) | 80 ft | 8.0 ft = 96 inches |
| Triangle frame — base (side to side) | 40 ft | 4.0 ft = 48 inches |
| Each leg length | 19 ft | 1.9 ft = 22.8 inches |
| Leg chord (width in flow direction) | 10 ft | 1.0 ft = 12 inches |
| Leg thickness (max) | 3 ft | 0.3 ft = 3.6 inches |
| Submerged depth per leg (50%) | 9.5 ft | 0.95 ft = 11.4 inches |
Each scale leg is a NACA foil 22.8″ long × 12″ chord × 3.6″ max thickness.
Volume of one scale leg ≈ 0.475 cubic feet
Foam density = 2 lb/ft³ → Weight of one finished scale leg ≈ 0.95 lbs
| Component | Volume (cubic feet) | Volume (US cups) |
|---|---|---|
| Part A | 0.2375 ft³ | 56.9 cups |
| Part B | 0.2375 ft³ | 56.9 cups |
| Total Mix | 0.475 ft³ | 113.8 cups |
Note: Most 2 lb/ft³ foam kits are mixed 1:1 by volume. Measure carefully — foam expands significantly.
| Item | Target Weight (lbs) |
|---|---|
| Full scale seastead (3 legs + triangle frame + payload) | ≈ 28,400 lbs (target displacement) |
| 1/10th scale model (3 foam legs + frame + ballast) | 28.4 lbs |
Scale weight is 1/1000th of full scale per Froude similitude (volume scales as λ³ = 1000).
Full scale speed = 5 knots = 8.439 ft/s
Scale speed (Froude) = full speed / √10 ≈ 8.439 / 3.162 ≈ 2.67 ft/s
Tow the model at 2.67 feet per second
Force scales with λ³ = 1000
Velocity scales with √λ = √10 ≈ 3.162
Power therefore scales with λ³ × √λ = 1000 × 3.162 = 3162
Multiply the drag force measured on the scale model (in lbs) by 3162
to get the approximate electrical power in watts required for the full-scale thrusters at 5 knots.
This assumes similar propulsive efficiency. Real-world thruster efficiency should be applied separately.
Time (and therefore roll period) scales with √λ = √10 ≈ 3.162
Measured model roll period × 3.162 = Full-scale roll period
All calculations use standard Froude scaling for marine models (gravity-dominated flows).
Caribbean seawater density ≈ 64.0 lb/ft³ used for displacement targets.
Foam volume calculated from approximate NACA foil geometry; minor adjustments may be needed after first pour.