How Voydar works

Where the data comes from

Voydar combines several public datasets. Each page names the specific source behind its numbers; the full list is below.

AIS (Automatic Identification System)Public radio broadcast

Live position, course, speed, heading, navigational status and reported destination, broadcast by vessels and received over public AIS feeds (AISstream.io, BarentsWatch, Digitraffic) and the Voydar receiver network.

BarentsWatch — live AISNLOD 2.0

Live positions for Norwegian waters, the Norwegian Sea and the Barents Sea, and currently one of our two largest live feeds. Contains data under NLOD made available by BarentsWatch.

Kystverket (Norwegian Coastal Administration) — live AISNLOD 2.0

Kystverket’s open terrestrial AIS network off the Norwegian coast, Svalbard and Jan Mayen. Contains data under NLOD made available by Kystverket. Configured, but this feed is not reachable at present, so today’s Norwegian coverage comes from BarentsWatch.

Digitraffic Marine (Fintraffic) — live AISCC BY 4.0

Live positions and vessel metadata for Finnish and Baltic waters. Source: Fintraffic / digitraffic.fi. This is a separate Digitraffic feed from the Finnish port-call data shown on Finnish port pages.

NOAA NDBC & CO-OPSU.S. public domain

Marine conditions near ports — wind, waves, water and air temperature from weather buoys and tide gauges.

NOAA Marine Cadastre — historical AISU.S. public domain (CC0)

Daily U.S. Coast Guard AIS records for U.S. waters, published by NOAA and BOEM. Voydar learns its sea-lane network for the sea-distance and ship-ETA tools from a sample of these days.

USCG PSIXU.S. public domain

Port State Control / Coast Guard inspection records: inspections, detentions and deficiencies recorded in U.S. waters.

EU MRV / EMSA THETIS-MRVEuropean Commission open data

Independently verified annual CO₂ and fuel figures for ships over 5,000 GT calling at EU/EEA ports (EU Regulation 2015/757).

OFAC SDN listU.S. public domain

U.S. Treasury Specially Designated Nationals list, matched to vessels to flag sanctions exposure.

UK Sanctions ListOpen Government Licence v3.0

UK government (FCDO) designations, including ships named by IMO number with their designation date and regime. Contains public sector information licensed under the Open Government Licence v3.0.

Canadian autonomous sanctions listOpen Government Licence – Canada

Global Affairs Canada consolidated autonomous sanctions (SEMA / JVCFOA), including ships named by IMO number with their listing date. Contains information licensed under the Open Government Licence – Canada.

Wikidata & WikipediaCC0 / CC BY-SA

Vessel and shipwreck particulars and narrative history, used to enrich identity records.

How we compute statistics

• Fleet and registry stats (fleet size, average age, gross tonnage, detention rate) are computed directly from Voydar's own records — never estimated or invented. A detention rate is detentions ÷ recorded inspections for that registry; where there are no inspections on record, we say so rather than show a zero.
• Coverage is honest. Counts reflect what Voydar has ingested, not the entire world fleet. As AIS coverage and the receiver network grow, the numbers grow with them.
• No keyword or number dumps. Tabular data is always wrapped in plain-language interpretation and a clear use case — a vessel page tells you what its safety record means, not just a wall of figures.

Automation & how pages are made

Voydar's pages are generated programmatically from structured data, with the prose templated and filled from each entity's own facts. We publish a page only when it carries a genuinely unique data point; thin records (a bare name with no particulars, position or history) are kept live but marked noindex and held out of the sitemap until they earn real data. Every page is built to help the person who landed on it, not to manipulate ranking.

Freshness

Live positions update as AIS messages arrive. Vessel, port and registry pages are cached and revalidated on a schedule (typically 15–60 minutes) so the server-rendered facts stay current without re-querying on every request. Where a page shows a "last detected" or "updated" time, that timestamp is the real recency of the underlying data.

Behaviour at sea: how Voydar derives it

Some vessel pages show patterns Voydar derived from the ship's own AIS broadcasts. They are inferences, not reports and not allegations: each carries the method and version that produced it, the inputs, and a confidence. Only detections of medium confidence or higher are shown, and only from feeds whose terms allow display on Voydar.

• AIS gap: no position for 4 hours or more, after we had heard the ship regularly, while the same receivers kept hearing other ships where it should have been. Gaps far from shore, where we cannot hear anyone, are never reported.
• Position anomalies: a move no ship can make (held back for an hour to rule out glitches), one MMSI shown in two places, or one IMO broadcast by two ships at once. These usually mean GNSS interference or a misconfigured transmitter.
• Ship-to-ship transfer candidate: two tankers or bulkers within 250 m at low speed for 2 hours or more, away from ports and anchorages. A sanctions listing of either ship is shown separately, with its source.
• Loitering: 12 hours or more inside a 10 km circle, not anchored, away from ports and anchorages.
• Draught change: the crew-reported draught changed in port or soon after sailing; Voydar infers loading or discharge.
• Predicted arrival: learned from past transits between the same two ports in our own port calls, with a likely range.

Tools

Our tools compute answers from the same data as the rest of the site. Sea distances follow a network of lanes learned from AIS position history; each graph records which feeds it was built from and is published only while all of them allow it. Ship ETAs use only positions from feeds that let us display them. Port conditions come from NOAA buoys and tide predictions. All tool results are derived estimates, labelled as such, and are not for navigation.

Maritime tools

Verifying & correcting data

Sanctions and inspection findings are serious; always confirm a match against the cited primary source — the OFAC Sanctions Search for sanctions, USCG PSIX for inspections, and EMSA THETIS-MRV for emissions. If you spot an error, you can help improve coverage and accuracy by hosting a receiver or getting in touch.