Tanker Classes Explained
Tanker names — VLCC, Suezmax, Aframax — sound like jargon but encode something simple: how much a ship carries, and therefore what its movements mean. When a single vessel leaving the Gulf can carry two million barrels, telling classes apart is most of the work of reading oil flow. Here is the full ladder, and how each class appears in our live Hormuz data.
The crude carriers
| Class | Deadweight (DWT) | Typical cargo | Notes |
|---|---|---|---|
| ULCC | 320,000+ | ~3 M bbl | Ultra Large Crude Carriers; only a handful in service. |
| VLCC | 180,000–320,000 | ~2 M bbl | The workhorse of Gulf→Asia crude. One VLCC/day ≈ 2 M bbl/day. |
| Suezmax | 120,000–200,000 | ~1 M bbl | Largest class that transits the Suez Canal fully laden. |
| Aframax / LR2 | 80,000–120,000 | ~0.7 M bbl | Flexible size for regional trades and smaller ports. |
| Panamax / LR1 | 55,000–80,000 | ~0.5 M bbl | Old Panama Canal limit; today mostly product trades. |
Product, chemical and gas carriers
- Product tankers (MR, ~25,000–55,000 DWT): carry refined fuels — diesel, jet fuel, gasoline — from Gulf refineries to nearby markets.
- Chemical/product tankers (10,000–50,000 DWT): coated or stainless tanks for petrochemicals, methanol, lubricants; a large share of everyday Hormuz traffic.
- LNG carriers (measured in m³, typically 150,000–266,000 m³): Qatar's entire export trade. They are the most risk-sensitive ships in the strait — LNG transits nearly vanished from our outbound record as the war intensified (see the timeline).
- LPG carriers (VLGC, ~50,000–60,000 DWT): propane and butane, mostly to Asian petrochemical buyers.
How classes map to our data
The tracker classifies each vessel from its AIS ship-type data into categories you'll see across the dashboard, using MarineTraffic's detailed vessel types: Crude Oil Tanker, Oil Products Tanker, Oil/Chemical Tanker, LNG Tanker, LPG Tanker, and the non-oil classes (bulk carriers, container ships, vehicle carriers, general cargo, and the Gulf's ever-present landing craft and service craft). Oil-flow estimates count the crude, oil products and oil/chemical tanker categories on outbound crossings; LNG/LPG estimates count LNG, LPG and LPG/chemical carriers.
Why class mix matters in wartime
Risk reshapes the fleet before it reshapes volumes. Charterers split cargoes across smaller hulls to spread insurance exposure; VLCCs wait out flare-ups at anchor while Aframaxes keep short regional runs alive; dark-fleet crude moves on ageing VLCCs with transponders off. Watching which classes cross — not just how many — is often the earliest signal in the data. The monthly statistics archive breaks every month down by vessel type for exactly this reason.