LightShip 33
Calibrate against the real boat ↗Measured loaded mass, CG datum, resting waterline and running trim still needed.
That was a big one.
The preview reached its motion limit. This is not a prediction of a real crash or capsize.
Calmer restart: 25 kn · 0.6 m waves · 4 s period.
View & settings
Starting approximate motion model…
121 components from the configurator’s 2601-A02-W-sourced-parts.STEP display model. Visual waterline and finishes; archipelago imagery is AI-generated. Wake, whitecaps and spray are illustrative effects, not solved flow or propeller predictions. Travel is straight; sea heading sets incoming waves, not steering. Motion uses sampled A13 hull volumes, assumed inertia and a Savitsky-inspired dynamic lift extension. Artificial closures and CAD registration remain unverified. No validated running trim, impact loads, comfort or speed predictions. Model source
Original STEP geometry · touch and keyboard controls available.
2D wave preview · height and period only. Direction is shown in 3D; boat response is not simulated.
Regular height or irregular Hm0 up to 4 m. Choose patterns and seeds in Sea state & hull inspection below. Waves fade in over 3 s after reset. Period has a conservative height-based minimum; this does not model breaking. Buoyancy uses sampled A13 CAD with unverified closures. Lift, damping and impacts remain approximate.
Sea state & hull inspection
Regular wave height is crest to trough.
Cyan: submerged hull samples · orange: dry samples · pale grid: sampled water surface · yellow: buoyancy centre · white: assumed CG. This is a sampled inspection overlay, not an exact waterline intersection.
Loading geometry audit…
CG and drive installation are unconfirmed. The reference CG is provisionally aligned with the calm-water buoyancy centre. These are model assumptions, not measured inputs.
Same sea. Different setup.
Scenarios stay on this device. Export a file to share them.
Both runs use this setup, the same wave seed and identical initial phase. Speed changes encounter timing.
Waterline & motion audit Geometry, buoyancy and constraints
Running trim and lift remain unvalidated. The at-sea preview integrates gravity, CAD-derived quadrature buoyancy and contact damping in heave, pitch and roll. Optional lift uses the dynamic part of the Savitsky correlation with local sampled bottom slopes; its extension to transient waves and the drive lever remain uncalibrated. It can lose water contact; no prescribed trim curve or crest attachment is used. The latest actual CFD case still fixes the hull in place.
At estimated 4,100 kg and assumed seawater density 1,025 kg/m³, displacement must be 4.00 m³ (40.2 kN buoyancy). The closed A13 mesh reproduces that at a zero-trim waterline 0.5104 m above the historical keel reference. This is force balance only; CG and moment balance remain unresolved.
The provisional display-to-A13 alignment places that waterline 86 mm below the display’s original z=0 waterline. Neither the display waterline nor the artificial hull closures are validated. The updated preview integrates 648 columns from the closed A13 triangulation without volume renormalisation. Its 4,100 kg zero-trim waterline is about 0.7 mm from the earlier surface integration. A finer grid changes it by about 0.4 mm. Artificial closures and correspondence to the displayed CAD remain provisional. CG is assumed at the 4,100 kg buoyancy centre, with VCG 0.8 m above the historical keel; the reported 2,750 mm reference still lacks a confirmed datum.
Drive installation: not verified. Earlier free-motion templates allow heave and pitch at historical 3,500 kg. No verified drive/thrust position, trim angle or propeller-force model is present. A drive installation must not be represented by silently fixing the boat to the world.
Working estimates: 3,600 kg dry + 200 kg fuel + 300 kg people/load = 4,100 kg. CG 2,750 mm is a photo-based estimate; datum/direction and vertical CG are unknown. These are assumptions, not measured inputs.
Download model audit and assumptions · Preview equations and limitationsWhat the solver actually did.
Recorded startup history · not recalculated by the test settings above.
R18 remains the flow reference. The latest repair tests have not produced an accepted performance mesh. R19 removes every wall layer; R20 changes quality only marginally. R21 reduces flags at the cost of three-layer coverage (34.6% to 22.4%). R22 lowers poor-determinant cells to two but reduces wall-layer coverage to 44.1% and fails three checks. No repair is promoted as an accepted mesh.
| Mesh | Poor determinants | Concavity flags | Wet area ≥1 layer | Wet area ≥3 layers |
|---|---|---|---|---|
| R18 | 14 | 2,823 | 80.4% | 34.6% |
| R19 | 0 | 486 | 0.0% | 0.0% |
| R20 | 13 | 2,865 | 80.8% | 34.2% |
| R21 | 12 | 2,357 | 81.4% | 22.4% |
| R22 | 2 | 2,198 | 44.1% | 11.7% |
R18: internal smoothing. R19: layer suppression buffer. R20: face splitting. R21: wider graded termination. R22: stricter tetrahedron quality. R19–R22 are mesh-only tests; fewer flagged cells alone does not establish adequate wall resolution.
Longer R18 flow saved through 25.02 ms. Final air/water speed maxima: 25.47/15.97 m/s. Stop: normal completion. This is 3.9% of one hull transit at the imposed 30 kn. Forces remain startup evidence.
Why mesh checks disagree: all 14 flagged R18 cells pass the builder’s whole-cell determinant check but fail the final internal-face connectivity check. The two measures are different; the final failure is retained.
Download latest findings and remaining work · Download boat reference
- Boat setup: 4,100 kg and equipment recorded; CG datum/direction and vertical CG still needed.
- Mesh: repair remaining connectivity and shape defects while retaining wall layers.
- Flow: establish loaded equilibrium, longer stability and settled forces.
- Performance: mesh/time-step sensitivity and sea-trial validation pending.
Measure the boat. Compare running trim.
Fill or print the measurement sheet for mass, CG datums, drafts, sealed hull and drive/propeller geometry. Import sea-trial observations to compare measured running trim with assumed-model benchmarks. Calibration and held-out records stay separate; unknown inputs remain unconfirmed.
Explore the assumption checks
51 paired cases covering 3,600–4,500 kg, 20–40 kn, assumed CG shifts of ±300 mm, VCG 0.6–1.0 m, and regular, irregular and crossing seas. All 33 calm-water cases settled; all 18 wave cases stayed within the chosen time-step comparison limits. Compare the paired traces and outputs; this is not real-boat validation.
Open interactive comparison review ↗ · Download findings · Download paired results
Default 0–30 kn runs now settle
The corrected lift calculation includes upward/downward contact velocity relative to the water. The same 4,100 kg setup now settles in 60-second flat-water runs at both tested time steps, including 25 and 30 kn. Mass, assumed CG, lift coefficients and damping constants were unchanged.
| Speed | Bow-up trim | Rise from rest at assumed CG | Finding |
|---|---|---|---|
| 0 kn | 0.00° | -0 mm | Numerically settled |
| 10 kn | 0.27° | 6 mm | Numerically settled |
| 15 kn | 0.88° | 33 mm | Numerically settled |
| 20 kn | 1.23° | 61 mm | Numerically settled |
| 25 kn | 1.44° | 92 mm | Numerically settled |
| 30 kn | 1.54° | 123 mm | Numerically settled |
Halving the time step changes the settled trim by less than 0.001° and rise by less than 0.001 mm. This checks numerical consistency for these default cases; it does not confirm the boat's real running trim or validate other loads, CG positions, drive settings or waves.
The old 25–30 kn formulation remained oscillatory. Its results are preserved below. Browser/device visuals remain unchecked here. No new CFD solution was run.
Download corrected findings · Download numerical results · Previous formulation findings · Previous results
What we need to finish
Target: one trustworthy 4,100 kg calm-water result, checked against the real boat.
- LW team: mark the CG reference and direction for 2,750 mm; provide vertical CG and the loaded weight breakdown.
- LW team + CAD: confirm sealed hull surfaces near the heavier-load waterline and provide measured bow/stern drafts.
- CFD: repair remaining mesh defects, establish loaded equilibrium and near-wall resolution, then demonstrate stable settled forces and numerical sensitivity.
- LW team: confirm the drive model/ratio and both propeller markings; collect paired reciprocal sea-trial observations.
- Validation: compare the accepted model with measurements before engine/propeller matching or wave predictions.
Provisional mass-only calculation: 4,100 kg displaces 4.00 m³ at assumed seawater density 1,025 kg/m³. Holding trim at zero raises the waterline about 36 mm. Artificial closure patches require review; this is not a loaded-equilibrium result and has not changed the CFD setup.
Download full status and remaining-work list · Download engineering input sheet
Sea-trial log
Quick entry: time, RPM and GPS speed. Add fuel flow when available. Measurements stay separate from simulated results.
Public shared log · no sign-in required. Anyone with the link can read, add and edit observations. Do not enter private information.
Connecting to the saved log...
The live cockpit shares saved observations with everyone using this link. The portable review exports observations to files; it cannot save to the online log. Exported CSV contains the loaded records only.
| Date / time | RPM | Speed · kn | Fuel · L/h | L/nm | Load · kg |
|---|
Measured-data comparison pending: no observations loaded. There is no validated CFD performance curve yet.
Observation edit history
History is retained from this update onward. For existing observations, the first retained entry is their current state. Restoring loads an earlier version into the form; review it and save to create a new revision.
No observations loaded.