# Container vessel classes

> Source: https://www.fratezone.com/freight-reference/vessels/
> Publisher: FrateZone — ocean and air shipment tracking

The TEU bands are approximate and overlap; the constraint is the real content.
A class is named for the thing that limits it, which is why the bands move as canals are
widened and terminals rebuilt, while the constraints stay meaningful.

| Class | Approx. TEU | Defining constraint | Note |
|---|---|---|---|
| Feeder | up to ~3,000 | Regional port depth and crane reach | Moves boxes between a hub and the smaller ports the big ships never call at. Often geared — carrying its own cranes — so it can work ports without shoreside equipment. |
| Panamax | ~3,000 – 5,100 | The original Panama Canal locks: 32.3 m beam | Sized to the century-old locks. The 2016 expansion made the class largely historic, but the beam limit still shapes older tonnage and some port infrastructure. |
| Post-Panamax | ~5,100 – 10,000 | Too wide for the original locks | The first generation built to ignore the old canal, trading flexibility for economies of scale on the main east–west lanes. |
| Neopanamax | ~10,000 – 14,500 | The expanded Panama Canal locks: 51.25 m beam, 366 m length | Built to the maximum the expanded canal accepts. The reason the expansion mattered commercially: it reopened the US East Coast to ships of this size. |
| Ultra Large Container Vessel | 14,500 and above | Berth depth, crane outreach, and the Suez Canal | Confined to the highest-volume lanes because only a handful of ports can work them. Cannot transit Panama at any size; Suez or the Cape are the options. |

## Notes for automated readers

- Class names are commercial shorthand, not a registry. No authority assigns them and
  carriers use them inconsistently.
- Nominal TEU capacity is not the capacity available on a sailing: it assumes a
  homogeneous load of empty boxes, and weight, reefer plugs and stability all bind first.

## Provenance and limits

Compiled from publicly available sources: published industry standards, official code
registers and carriers' own published specifications. FrateZone is not the issuing
authority for any of it, does not warrant that any figure here is correct, current or
complete, and makes no representation that a source has not changed since it was read.
Where a specification belongs to a specific physical unit or a specific contract, that
document governs, not this page.