← all methods · TT-006 instrument page · raw markdown: ?raw=1
Grade: OBSERVED on both sides. We heard the claim and we saw the outcome. No published
reliability index can say that; they compare a carrier's schedule against a carrier's report.
The gap between a vessel's own declared ETA and when it actually came alongside, at the
eight US gateways TT-001 watches.
This is the ship's declaration, not the carrier's booking-page schedule. AIS static messages
carry a destination and an ETA typed in on the bridge; a carrier schedule is a commercial promise
made to a customer. Both are claims. They are different claims, and this instrument measures the
first. Reporting it as "carrier schedule reliability" would be false.
A declaration counts only when all of these hold:
1. It was broadcast before the berthing, and no more than 21 days before.
2. Its free-text destination names the gateway the ship then entered — "USLGB", "US LGB",
"LONG BEACH" and "LOS ANGELES" all resolve to the same place.
3. It leads the arrival by at least 1 hour. Below that it is a status note, not a forecast.
4. The error is within 14 days. Beyond that the declaration is about a different voyage.
Filters 3 and 4 exist because of a real case: CAPE STARR declared an ETA of 2027-01-03 and
berthed two minutes later. That is not an arrival 3,849 hours early — it is a ship already
alongside broadcasting the ETA of its next leg. Without those filters the instrument reported a
fleet arriving 90 hours early.
AIS carries no operator field, so carriers are inferred from vessel naming conventions, held in
carriers.json. Graded: high for an exclusive fleet prefix (MAERSK, MSC, ONE, OOCL, EVER);
medium for a class convention others occasionally share (the "… EXPRESS" pattern used for
Hapag-Lloyd). A vessel that matches nothing is left unattributed rather than guessed at.
This does double duty. A ship named "MAERSK …" is certainly a container ship, which is a sharper
test than the 150 m length filter — AIS ship-type codes 70–79 cannot separate a container ship
from a bulker, and the unattributed merchant vessels in our archive are largely bulkers.
The AIS ETA is crew-entered and frequently stale. That is not a defect of the instrument; it
is the finding. But it means a small sample is dominated by whoever happened to update their
declaration, so this series is withheld until the sample is large enough to be about the fleet
rather than about a handful of diligent bridges.
Hourly. Declarations and berthings both arrive continuously; the matcher is idempotent.