{
  "slug": "tt009.gateway.anchor-wait-hours",
  "name": "Hours waiting at anchor before a berth",
  "unit": "hours",
  "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": "Anchor time counted ONLY where a berth followed in the same visit. Ships also anchor for bunkers, stores, crew changes, weather and awaiting orders; none of that is queueing.",
  "instrument": {
    "id": "TT-009",
    "name": "Berth queueing",
    "clock": "fast",
    "role": "reporter",
    "source": "Own AIS receivers, via the TT-001 archive",
    "source_url": "https://ais.trimtabist.com/gateways"
  },
  "coverage": {
    "from": "2026-07-26",
    "to": null
  },
  "publishable_ranges": [],
  "status": "suspended",
  "withdrawn": {
    "since": "1970-01-01",
    "until": null,
    "reason": "RIGHT-CENSORED AND THIN. 44 of 206 calls anchored but had not berthed when the window closed, and those are the LONGEST waits, so the bias grows exactly when congestion is worst — in a crisis this would sag rather than spike. Only 92 of 1,241 observed anchor hours (7%) are verified as queueing. Usable once the archive exceeds the waits it measures.",
    "finding": null
  },
  "citation": "Trimtabist TT-009 Berth queueing, own AIS receivers, 10 US container gateways. Method: berthing/METHOD.md. Grade: observed.",
  "citationShort": "Trimtab TT-009 Berth queueing, \"Hours waiting at anchor before a berth\" (retrieved 2026-08-06).",
  "licence": "CC BY 4.0",
  "retrieved_at": "2026-08-06T11:20:48.016Z",
  "urls": {
    "page": "https://trimtabist.com/series/tt009.gateway.anchor-wait-hours",
    "csv": "https://trimtabist.com/series/tt009.gateway.anchor-wait-hours.csv",
    "metadata": "https://trimtabist.com/series/tt009.gateway.anchor-wait-hours.metadata.json"
  }
}