Comprehensive analysis of wave response characteristics from scale model testing, comparing performance against conventional catamaran and monohull vessels.
Froude scaling laws applied to transform model measurements to full-scale predictions.
| Parameter | Scale Factor | Model Value | Full Scale Value |
|---|---|---|---|
| Length | λ = 6 | 70 in (5.8 ft) | 35 ft |
| Beam/Width | λ = 6 | 23 in | 11.5 ft |
| Leg Diameter | λ = 6 | 8 in | 4 ft |
| Leg Length | λ = 6 | 48 in (4 ft) | 24 ft |
| Wave Height | λ = 6 | 6-10 in | 3-5 ft |
| Wave Period | √λ = 2.45 | ~1.0-1.5 s | ~2.5-3.7 s |
| Acceleration | 1:1 | Direct | Direct |
| Velocity | √λ = 2.45 | v | 2.45 × v |
Estimated wave heights from video analysis using known model dimensions as reference.
Comparing the seastead's motion characteristics to conventional 50' catamaran and 60' monohull vessels in equivalent conditions.
Up and down displacement from wave action
Angular displacement about longitudinal axis
Angular displacement about transverse axis
The narrow legs at the waterline present minimal surface area to wave forces. Unlike a boat hull that must push through waves, the spar "ignores" them.
High mass combined with low waterplane stiffness creates a heave natural period much longer than typical wave periods, avoiding resonance.
Most wave energy is concentrated near the surface. By placing buoyancy deep, the platform experiences attenuated wave forces.
Estimated vertical and lateral accelerations experienced at the living area deck level. Under Froude scaling, accelerations are 1:1 between model and full scale.
| Vessel Type | Vertical (g) | Lateral (g) | Comfort |
|---|---|---|---|
|
Spar Seastead
|
0.05-0.15 | 0.02-0.08 | Excellent |
|
50' Catamaran
|
0.15-0.30 | 0.10-0.20 | Good |
|
60' Monohull
|
0.20-0.40 | 0.15-0.35 | Moderate |
At 0.05-0.15g vertical, the spar seastead experiences motion similar to a very gentle elevator ride. Most people can walk normally, pour drinks, and perform daily activities without difficulty. This is 2-4x less motion than a catamaran and 3-5x less than a monohull in the same conditions.
Walking, cooking, sleeping - all remain comfortable even in moderate seas that would make a monohull unpleasant. Furniture stays in place. No sea sickness.
Equipment, solar panels, and infrastructure experience minimal stress. Docking small boats alongside is safer. Anchoring loads are reduced.
While boats must seek shelter in rough weather, the spar's motion characteristics allow it to remain habitable in sea states that would force vessels to port.
Based on analysis of the 1/6 scale model test video, the spar-type seastead demonstrates exceptionally favorable motion characteristics compared to conventional vessels.