Video: https://www.youtube.com/watch?v=EkQ17pU44Dw
Model scale (1:6) observed wave heights:
Full-scale equivalent (Froude scaling ×6):
The platform is behaving as a stiff, lightly damped triangular semi-submersible with very low waterplane area relative to its mass moment of inertia.
| Degree of Freedom | Model Observation | Projected Full-Scale (60 ft triangle) | Comparison to 50 ft Catamaran | Comparison to 60 ft Monohull |
|---|---|---|---|---|
| Heave (vertical) | Follows waves ~60–70% of wave height | ~0.9 – 1.6 ft in 2 ft waves | Similar to cat in short waves, but lower peak accelerations | Significantly less than monohull (monohull often 1.5–2× wave height) |
| Roll / Pitch | Very small angular motion (<4° model) | Estimated <3–4° in 2 ft beam seas | Better than most cats (cats can snap in roll) | Much better than monohull (monohulls often 10–20°+) |
| Yaw / Sway | Minimal yaw, slight orbital motion | Very stable heading | Comparable or better | Far superior to monohull |
Current (light) configuration — Full Scale:
With twice the weight (2/3 submersion) — Full Scale:
The increased mass and deeper draft raise the natural heave period and lower the Response Amplitude Operator (RAO) in the wave frequencies shown in the video.
Current draft is only ~1/3 of the column length. Doubling the displacement while keeping the same 3-column waterplane area would bring the draft to the desired ~2/3 submersion.
Benefits of the heavier configuration:
The 60 ft triangular seastead design shows excellent motion characteristics compared to both a typical 50 ft cruising catamaran and a 60 ft monohull. Roll and pitch motions are substantially lower than either conventional hull form. Vertical accelerations in the current light configuration are already competitive with a good catamaran; with the planned ballast the platform should feel noticeably calmer than most 50–60 ft recreational boats in 1.5–3 ft waves.
The three-column triangular arrangement is doing exactly what it was intended to do: provide a very stable platform with low angular motion. The next test with proper ballast should confirm a significant further improvement in ride quality.