{
  "slug": "tt001.us-gateways.cargo-worked",
  "name": "Draught change worked at US gateways",
  "unit": "metres/month",
  "horizon": "short",
  "grade": "observed",
  "grade_means": "Own-recorded live from terrestrial AIS (aisstream.io receiver network); the recording, timestamps and event derivation are ours.",
  "description": "Total absolute draught change reported by merchant vessels while inside a US gateway, per month. A proxy for cargo worked: a ship that arrives deep and leaves shallow has discharged. It is a proxy and not a measurement — draught is crew-entered, so a ship that works cargo and never updates is missed. This undercounts and never invents.",
  "instrument": {
    "id": "TT-001",
    "name": "Gateway watch",
    "clock": "fast",
    "role": "reporter",
    "source": "AISstream.io → own recorder",
    "source_url": "https://ais.trimtabist.com"
  },
  "coverage": {
    "from": "2026-07",
    "to": null
  },
  "publishable_ranges": [
    {
      "from": "2026-07",
      "to": "2100-01-01"
    }
  ],
  "status": "fit",
  "citation": "Trimtab TT-001 Gateway watch, own-recorded AIS static messages.",
  "citationShort": "Trimtab TT-001 Gateway watch, \"Draught change worked at US gateways\" (retrieved 2026-08-06).",
  "licence": "CC BY 4.0",
  "retrieved_at": "2026-08-06T11:20:19.549Z",
  "urls": {
    "page": "https://trimtabist.com/series/tt001.us-gateways.cargo-worked",
    "csv": "https://trimtabist.com/series/tt001.us-gateways.cargo-worked.csv",
    "metadata": "https://trimtabist.com/series/tt001.us-gateways.cargo-worked.metadata.json"
  }
}