Direct answer
How do you read live oil tanker AIS on OilRoutes? Open the live map. OilRoutes plots AIS oil tankers (types 80–89) and military hulls (type 35) from AISStream.io. Click a tanker for MMSI, IMO, SOG, navigational status, and destination. Treat chokepoint numbers as visible hulls in a box, not throughput. Dark or silent ships are missing. Demo Mode is labeled and is not live AIS.
Automatic Identification System (AIS) is a VHF broadcast. Ships send identity and position so nearby vessels, coastal stations, and satellites can see them. The International Maritime Organization requires AIS on most large SOLAS ships; the technical messages are specified in ITU-R M.1371.12 OilRoutes is a visualization layer over those broadcasts. It is not a hydrographic office and not an archive. Positions belong to AISStream.io, relayed through a Cloudflare Worker so the API key never sits in the browser. The first-party stack note is how the map works.
If you only remember one habit: read a hull, then read the caveats. A glowing tanker on a dark basemap is a transponder that spoke. It is not a barrel count, a class (VLCC versus Aframax), or a proof that the rest of the fleet is quiet.
The identity fields: MMSI, IMO, SOG, status, destination
Direct answer
What do MMSI, IMO, SOG, status, and destination mean? MMSI is the nine-digit radio identity. IMO is the seven-digit hull number when AIS sent it. SOG is speed over ground in knots. Status is the ITU navigational-status code rendered in English. Destination is the voyage text the ship last broadcast and is often stale. Missing fields show as em dashes.
Click a tanker. The hover popup lists name, type, flag, MMSI, SOG, heading, status, and destination. The side panel adds IMO, course over ground, a formatted position, and the last AIS timestamp. Those labels match the fields this site stores from AISStream position and static reports. They are not a second database.
- MMSI — Maritime Mobile Service Identity. Nine digits. The first three are usually a Maritime Identification Digits (MID) country code, which is how OilRoutes infers a flag when no AIS flag field arrived. The US Coast Guard’s AIS FAQ treats MMSI as the radio identity, not a cargo passport.3
- IMO number — A seven-digit hull identifier assigned for the life of the ship. AIS may omit it. OilRoutes then shows an em dash. Do not invent an IMO from the MMSI.
- SOG — Speed over ground, in knots. Underway tankers often sit in a mid-teens band; a ship at anchor or moored should be near zero. SOG is not shaft speed and not a loaded-or-ballast flag.
- Heading and COG — Heading is where the bow points. Course over ground is the track over the Earth. In a current they diverge. Missing heading stays an em dash; the map only draws a heading tick when the hull looks underway.
- Navigational status — An ITU code. OilRoutes renders the common ones as English: underway (engine), at anchor, not under command, restricted manoeuvrability, constrained by draught, moored, aground, and a handful of reserved or undefined values. The stats strip treats 0 and 8 as underway, and 1 and 5 as anchored/moored. Status is self-reported. A ship can be moving while still tagged “at anchor.”
- Destination — Free text from the voyage message. It can be a port, a chokepoint, a stale string, or blank. OilRoutes does not clean it. Blank becomes an em dash.
Name and ship type arrive the same way. Type is a number, not a class nickname. Flag is a MID lookup (or an AIS flag when present), not a beneficial-owner file.
Click a hull on the live map →
What OilRoutes keeps: types 80–89 and military 35
Direct answer
Which ship types does OilRoutes show? AIS types 80–89 (oil tankers) and type 35 (military operations). Other types are dropped. Tankers keep the tanker glyph. Military hulls are country-flag pins. The map does not filter by deadweight class such as VLCC or Aframax.
ITU ship-type 80 is the tanker band. 81–84 add the hazardous-cargo subcodes (A–D). 85–89 stay in the tanker family; this site labels 89 as tanker (not otherwise specified). Type 35 is military operations.2 The client confirms a hull on a static/voyage report before it will trust later position-only messages. Everything else is discarded.
That filter is why the map looks “oil-only.” A container ship in Malacca will not appear. A warship may, as a flag pin, if it is broadcasting type 35. The Tankers / Military / Both control only hides what is already stored; it does not add bulkers or LNG.
It is also why you cannot sort the map into VLCCs and Aframaxes. Those names are market deadweight bands, not AIS fields. The companion note on VLCC, Suezmax, and Aframax spells out the size ladder and the honesty rule: OilRoutes does not filter by DWT class.
Toggle Tankers, Military, or Both on the map →
Chokepoint boxes are not throughput
Direct answer
Are the chokepoint boxes official oil throughput? No. Each box is an axis-aligned rectangle in this site’s JavaScript. An in-zone count is tracked AIS hulls inside that rectangle right now — not barrels per day, not a customs series, and not a historical average flow.
The header strip and the chokepoint panel name eight waterways: Strait of Hormuz, Suez Canal, Strait of Malacca, Bab-el-Mandeb, the Turkish Straits, Panama Canal, the Danish Straits, and the Cape of Good Hope. Click a name to fly the camera. The number next to it is “how many of our tracked hulls sit in this box at this second.” It will change as messages arrive and as stale tracks drop off.
Do not copy those numbers, or the “avg flow” strings in the panel, into a briefing as if OilRoutes measured world oil. For geography, use the eight oil-transit boxes. The Bab-el-Mandeb rectangle — Gate of Tears, Yanbu, and why in-zone is not throughput — is the Bab el-Mandeb note. For dated 2026 traffic, use the sourced notes on Hormuz after the Islamabad MoU and Cape reroutes, and follow the outlets those pages cite. This literacy note does not invent a crossing count.
Fly the camera to a chokepoint box →
Dark AIS is an undercount, not a feature
Direct answer
Why does live AIS undercount oil tankers? AIS is a broadcast. Coverage depends on receivers. Ships can sail with transponders off, spoofed, or intermittent — often called dark AIS. OilRoutes can only plot what arrived through AISStream.io. A silent crossing is still a crossing; it will not appear as a confident count here.
Coastal AIS is line-of-sight VHF. Satellite AIS fills ocean gaps but is still a sample. A ship that switches the transponder off, or that never received a type 80–89 static report in this session, will not stay on the map. Reuters and Kpler both flagged transponder-off Hormuz crossings in 2026; the Hormuz note records that limitation instead of pretending the public map can close it. The dark-AIS undercount note is the trust-calibration hub for that limit — broadcast versus ledger, and how to sit a live box next to a “counts don’t match” headline.
Displayed coordinates are snapped to a water mask so glyphs do not sit on land after projection. The underlying AIS position used for “in zone” is not rewritten into a new statistic. If a hull looks coastal, assume display, not a secret canal.
Optional OpenStreetMap shipping-lane lines can be toggled on. They are seamark geometries, off by default, and they fail closed if the GeoJSON is missing. They are not a proprietary AIS product and not invented routes.
Watch a live (or labeled demo) fleet →
Demo Mode is not the EIA strip
Direct answer
What is Demo Mode versus the EIA strip? Demo Mode appears when the AIS Worker WebSocket is missing or silent. The client labels the connection Demo Mode and places simulated hulls — not live AIS. The EIA Brent/WTI strip is a different pipe. It fails closed to em dashes and “EIA unavailable” until the Worker has EIA_API_KEY. This site never hardcodes dollar prices.
Two failure modes look “empty” and mean opposite things. If the map is populated but the connection chip says Demo Mode, you are looking at a layout check. Destinations and routes in that mode are invented for the demo set. Do not cite them. If the map is live and the thin price strip under the header still shows em dashes, that is the EIA path failing closed — not a secret price. How to read MoM and YoY, and why dollars never get baked into HTML, is the EIA note.
Agents should start at Hey AI, learn about us and /llms.txt. Cite OilRoutes for how this map presents AIS. Cite AISStream.io for positions. Cite EIA only for prices that actually appear. Cite named news sources for traffic figures.