# Parametric hull design notebook

Revision 0.1 — 31 October 2026.

A runnable Python Jupyter notebook accompanies this page. It explains the recorded Carantec targets, how to choose inputs, which hypotheses are provisional, and how to iterate a candidate hull. Download the attached `.ipynb`, open it in JupyterLab/Notebook, edit the parameter cells and run all cells. Dependencies: Python 3.10+, numpy, pandas, scipy, matplotlib.

## Included

- A parameter and assumption register grounded in the [design roadmap](https://projects.alkemata.com/projects/cotre-carantec/wiki/cotre-carantec-62-design-and-project-roadmap).
- An editable symmetric hard-chine hull generator, body sections, waterplane and sectional-area plots.
- Upright flotation by mass equilibrium; displaced volume, KB, LCB, waterplane inertia and initial GM.
- Explicit illustrative component mass/CG register; light, day-sailing, overnight, maximum and sensitivity cases.
- Beam/taper/rocker alternatives, Froude number and small-angle righting-moment illustrations.
- Analytic rectangular-section/box checks, flotation residual and station-grid convergence.
- Optional HTTPS imports from Open-Meteo historical wind and marine forecast APIs, and the UCI Yacht Hydrodynamics dataset; raw-response caching, retrieval timestamps and checksums.
- Optional input, mass-register, results and station-polygon exports; task-by-task reconciliation plan.

## Evidence and limitations

The core offline calculation cells were executed successfully before upload. The maximum-load candidate waterline is about 0.4704 m above this notebook's hull-bottom datum; BM changes by less than 0.01% between 201 and 401 stations. These are results for an educational candidate, not verified results for the existing FreeCAD hull. Optional live data imports were not executed in this environment and are disabled by default; no downloaded dataset or live-weather results are claimed.

The linked CAD, original reports and DXF were not read through this connector. Shape controls and component CG allocations are clearly labelled hypotheses. Hull buoyancy excludes appendages; upright hydrostatics assume zero trim. The trim calculation is only a linear indication. No full GZ/downflooding analysis, scantlings, panel development or speed prediction is supplied. Existing wiki GM/GZ figures are not validated by this independent model. The notebook frame must be reconciled with CAD before comparing CG values.

## Next use in the project

Confirm inputs in [#47](https://projects.alkemata.com/work_packages/47), replace the mass placeholders in [#50](https://projects.alkemata.com/work_packages/50), reconcile geometry in [#52](https://projects.alkemata.com/work_packages/52), and extend validated stability in [#48](https://projects.alkemata.com/work_packages/48). The notebook supports investigation; it does not close these tasks or release construction at [M2](https://projects.alkemata.com/work_packages/46).

## Online references

- [Open-Meteo historical weather API](https://open-meteo.com/en/docs/historical-weather-api)
- [Open-Meteo marine API](https://open-meteo.com/en/docs/marine-weather-api)
- [UCI Yacht Hydrodynamics dataset](https://archive.ics.uci.edu/dataset/243/yacht+hydrodynamics)
- [ORC stability measurements](https://orc.org/measurements/stability)

Use model/provider attribution and current source terms. Reanalysis and forecasts do not establish design extremes, navigation advice or structural loads.