{
  "slug": "tt001.us-gateways.anchor-wait",
  "name": "Anchorage wait before berthing",
  "unit": "hours",
  "horizon": "short",
  "grade": "observed",
  "grade_means": "We watched it happen: our own AIS receivers (via the aisstream.io terrestrial network), our timestamps, our archive.",
  "description": "Mean completed time at anchor per day for merchant vessels at the monitored US container gateways. Same 70-79 / 150 m filter as the other TT-001 series.",
  "instrument": {
    "id": "TT-001",
    "name": "Gateway watch",
    "clock": "fast",
    "role": "reporter",
    "source": "AISstream.io → own recorder",
    "source_url": "https://ais.trimtabist.com"
  },
  "coverage": {
    "from": "2026-07-26",
    "to": null
  },
  "publishable_ranges": [],
  "status": "suspended",
  "withdrawn": {
    "since": "1970-01-01",
    "until": null,
    "reason": "SUPERSEDED. Computed from the crew-set NavigationalStatus field and the old event state machine, both disproven 2026-07-30: the status field recorded 153 anchor events against 3,273 berth events because crews rarely set it, and the state machine split single calls into fragments on speed noise. Replaced by position-based detection in berthing.db — see tt001.gateway.* and berthing/METHOD.md.",
    "finding": null
  },
  "citation": "Trimtab TT-001 Gateway watch, own-recorded AIS.",
  "citationShort": "Trimtab TT-001 Gateway watch, \"Anchorage wait before berthing\" (retrieved 2026-08-06).",
  "licence": "CC BY 4.0",
  "retrieved_at": "2026-08-06T13:40:37.581Z",
  "urls": {
    "page": "https://trimtabist.com/series/tt001.us-gateways.anchor-wait",
    "csv": "https://trimtabist.com/series/tt001.us-gateways.anchor-wait.csv",
    "metadata": "https://trimtabist.com/series/tt001.us-gateways.anchor-wait.metadata.json"
  }
}