sailboat-hydro

Zero-Network Python library for FairHelm sailboat hydrodynamic ratios and the Open European & Nordic Sailboat Benchmark (93 models).

Formulas and the JSON snapshot ship inside the wheel. Calls run locally. There is no HTTP to api.fairhelm.com, no Postgres, and no CapEx / listing decoder.

Install

pip install sailboat-hydro

From a local checkout of this monorepo package:

pip install -e "packages/sailboat-hydro[dev]"

Quick start

from sailboat_hydro import (
    hull_speed_kn,
    capsize_screening,
    displacement_length_ratio,
    comfort_ratio,
    sail_area_displacement,
    load_nordic_benchmark,
)

print(hull_speed_kn(9.35))                 # ~7.43 kn
print(capsize_screening(3.55, 7500))       # ~1.829
print(displacement_length_ratio(7500, 9.35))
print(
    comfort_ratio(
        displacement_kg=7500,
        lwl_m=9.35,
        loa_m=10.87,
        beam_m=3.55,
    )
)

bench = load_nordic_benchmark()            # 93 models, local JSON only
hr36 = bench.get("hallberg-rassy", "hr36")
assert hr36 is not None
print(hr36.name, hr36.hull_speed_kn, hr36.canonical_model_url)
print(bench.zenodo_doi)

API

Formula constants match @nareyko/mcp-yacht-specs (packages/mcp-yacht-specs/src/formulas.ts) and the FairHelm frontend formula SSOT. Refresh the bundled JSON with:

python packages/sailboat-hydro/scripts/sync_benchmark.py

Citation

Please cite FairHelm formulas and the Zenodo deposit:

@misc{fairhelm_sailboat_benchmark_2026,
  title        = {Open European \& Nordic Sailboat Benchmark (93 Models)},
  author       = {Nareyko, Vadim and FairHelm},
  year         = {2026},
  doi          = {10.5281/zenodo.23374417},
  url          = {https://doi.org/10.5281/zenodo.23374417},
  howpublished = {FairHelm / CERN Zenodo},
  note         = {Methodology: https://fairhelm.com/en/yachts/formulas/}
}

Also see CITATION.cff.

Develop / test

cd packages/sailboat-hydro
python -m pip install -e ".[dev]"
ruff check .
mypy src
pytest -q

Publish (owner)

See PUBLISH.md. Build artifacts land in dist/.

License

MIT. See LICENSE.