What is the AIS ship type field?

AIS, the Automatic Identification System, broadcasts a two-digit ship type number defined by ITU-R M.1371. The first digit gives the broad category, such as 7 for cargo or 8 for tanker, and the second digit refines it. Lloyd's Register and AIS traffic services use it as the basis for fleet type labels.

What do cargo and tanker type numbers look like?

Cargo ships use 70 to 79 and tankers use 80 to 89. The first digit fixes the broad type and the second digit signals a dangerous-cargo category from A to D, so 80 is a tanker with no hazard specified while 84 is a tanker carrying dangerous goods of hazard category D.

How is a passenger ship coded?

Passenger ships and ferries use the range 60 to 69. As with cargo and tankers, the second digit carries a dangerous-cargo category A to D, though for most passenger ferries the value is 0 meaning no hazardous cargo is specified.

Does AIS distinguish a bulk carrier from a container ship?

Not directly. Both are simply cargo, code 70 to 79, in the raw AIS field. Lloyd's Register and traffic services derive finer labels such as bulk carrier, container ship, or general cargo by combining the AIS type with the ship's deadweight, dimensions, and registered design data.

What do the type numbers 30 to 37 cover?

These are special-purpose small craft: 30 fishing, 31 and 32 towing, 33 dredging or underwater operations, 34 diving, 35 military operations, 36 sailing, and 37 pleasure craft. Unlike the cargo and tanker groups, these do not use a hazardous-cargo second digit.

Lloyd's Vessel Type Reference

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Reading vessel type codes

Ship type in Lloyd’s Register and live AIS marine-traffic feeds is built on the two-digit ship type field broadcast by every AIS transponder, defined in ITU-R M.1371. This reference decodes that number into a broad category — cargo, tanker, passenger, tug, fishing, and more — and explains the hazardous-cargo second digit.

How it works

The number is read as two digits with distinct jobs:

first digit  : broad category
  3x  special small craft (fishing, towing, sailing...)
  4x  high-speed craft
  6x  passenger
  7x  cargo
  8x  tanker
second digit : for WIG/HSC/passenger/cargo/tanker, a hazard category
  0 none specified   1 cat A   2 cat B   3 cat C   4 cat D

So 70 is a cargo ship with no hazard specified, 80 a tanker, and 84 a tanker carrying category-D dangerous goods. The 30-series codes are individual special-purpose craft (fishing, towing, dredging, diving, sailing, pleasure) and do not use the hazard digit.

Tips and notes

The raw AIS code is deliberately coarse: every dry-cargo ship is 7x whether it is a bulk carrier, a container ship, or general cargo. The richer vessel-type names you see in Lloyd’s Register and commercial traffic services come from combining this field with the ship’s deadweight tonnage, hull dimensions, and registered design, plus the IMO number that uniquely identifies the hull. Treat the AIS type as a starting category, not the final classification.