Not everything fits in a standard container. Machinery, vehicles, steel structures and large moulds often need a flat rack container, an open top container or a breakbulk ship. This guide explains the options for shipping oversized cargo from China, their typical dimensions, how costs are calculated and how to prepare your shipment.
Key points
• Oversized or out-of-gauge (OOG) cargo is too long, wide, tall or heavy for a standard container.
• Flat rack containers have no roof or side walls, for cargo that is too wide or too tall. Open top containers have a removable roof, for tall cargo loaded by crane.
• Very large or heavy pieces may go as breakbulk, loaded directly onto the ship.
• OOG freight costs more because over-width or over-height cargo blocks space next to it. Exact dimensions and weights are needed for every quote.
• Space for flat racks and open tops is limited, so book early.
What Is Oversized (OOG) Cargo?
Cargo is “out of gauge” when it exceeds the inside dimensions or the weight limit of a standard 20ft or 40ft container. Typical examples from China include:
- Machinery and equipment: CNC machines, presses, generators, production lines.
- Vehicles: trucks, buses, construction machinery, boats.
- Steel structures: beams, frames, tanks, prefabricated buildings.
- Other large items: moulds, transformers, large crates.
A standard 40ft container is about 2.35 m wide and 2.39 m high inside, with a door about 2.28 m high. See shipping container dimensions for the full specs.
Flat Rack, Open Top or Breakbulk?
| Flat rack container | Open top container | Breakbulk | |
|---|---|---|---|
| What it is | A floor with end walls, no roof or side walls | A container with a removable tarpaulin roof | Cargo loaded piece by piece into the ship’s hold or on deck |
| Best for | Over-width and over-height cargo, heavy machinery, vehicles | Tall cargo that fits the width, loaded from above by crane | Very large or very heavy pieces, project cargo |
| Loading | From the sides or above, by crane or forklift | From above by crane, or through the doors | By ship or port crane |
| Protection | Exposed to weather; needs wrapping and lashing | Covered by a tarpaulin | Depends on stowage |
| Sizes | 20ft and 40ft, often collapsible | 20ft and 40ft | No size limit within the ship’s capacity |
Flat Rack Container Dimensions
Flat racks are often collapsible: the end walls fold down so empty units can be stacked. Typical figures from a major carrier:
| 20ft flat rack | 40ft flat rack | |
|---|---|---|
| Length between end posts | about 5.6 m | about 11.6 m |
| Width between posts | about 2.2 m | about 2.2 m |
| Tare weight | about 2.7 t | about 6 t |
| Maximum payload | about 31–42 t | about 44–54 t |
Because a flat rack has no side walls, the cargo can be wider than the rack, and taller than a container stack. That over-width and over-height is exactly what makes flat racks useful, and what drives the price.
Open Top Container Dimensions
| 20ft open top | 40ft open top | |
|---|---|---|
| Inside length | about 5.9 m | about 12.0 m |
| Inside width | about 2.35 m | about 2.35 m |
| Inside height | about 2.35 m | about 2.35 m |
| Maximum payload | about 30 t | about 26–28 t |
Cargo can stick out above the top of an open top container, with the tarpaulin fitted over it, but this counts as over-height and is priced like a flat rack.
Container specifications vary by carrier and manufacturer. We confirm the exact figures for the container booked for your shipment. Source for typical values: Hapag-Lloyd container specifications.
How Oversized Cargo Is Priced
OOG shipments are always quoted individually. The main cost factors are:
- Over-width and over-height: cargo that sticks out over the sides or top blocks the slots next to or above it on the ship, so the carrier charges for that lost space.
- Weight: heavy pieces may need special cranes, extra lashing or a heavier-rated container.
- Lashing and securing: chains, straps, timber blocking and a lashing survey where required.
- Crating and protection: export crates, rust protection and waterproof wrapping, especially on open flat racks.
- Inland transport: oversized trucking in China may need special trailers, route checks and permits.
- Port handling: terminals charge extra to handle OOG units.
For an accurate quote, send the length, width, height and weight of each piece, the lifting points, and a drawing or photos.
How to Ship Oversized Cargo from China
- Send the cargo details: dimensions, weight, drawings or photos, and where the cargo is.
- Choose the equipment: flat rack, open top or breakbulk, and the best route and port.
- Book early: flat racks and open tops are limited, and carriers need to approve the stowage plan.
- Prepare the cargo: crating, rust protection and wrapping, and draining fluids from vehicles and machinery where required.
- Load and secure: at the factory or at a port facility, with proper lashing and photos for your records.
- Inland transport and export clearance: oversized trucking to the port and customs declaration in China.
- Destination: import clearance, unloading and delivery. Plan the unloading equipment at your site in advance.
Risks and How to Avoid Them
- Wrong dimensions: even a few centimetres can change the equipment or the price. Measure the packed cargo, not just the machine.
- Poor lashing: carriers can refuse badly secured cargo at the terminal, causing delays and extra costs.
- Weather damage: cargo on a flat rack is exposed for weeks at sea. Use good wrapping and rust protection.
- Limited space: OOG cargo can be rolled to a later ship if space is tight. Book early and keep in close contact with your forwarder.
- Insurance: heavy and oversized cargo carries more risk in handling. See cargo insurance.
Example: Shipping a CNC Machine from Guangdong
A machine packed on a steel skid measures 6.8 m long, 2.6 m wide and 2.5 m high and weighs 9.5 t.
| Check | Result |
|---|---|
| Fits a 40ft standard or high cube container? | No: 2.6 m is wider than the inside width of about 2.35 m |
| Fits a 40ft open top? | No: too wide for the side walls |
| Fits a 40ft flat rack? | Yes: 6.8 m fits the length; it is over-width by about 0.4 m in total |
| Weight | 9.5 t is well within the flat rack payload |
| Price drivers | Over-width charge, lashing and a lashing survey, crane loading at the factory, oversized trucking to the port |
| Timeline | Carrier approval of the stowage plan before booking is confirmed; allow extra days compared with a normal container |
The same machine at 2.3 m wide would fit a 40ft open top or even a standard high cube with the right loading equipment, at a much lower cost. That is why exact packed dimensions matter so much.
What to Send for an Oversized Cargo Quote
| Information | Why it matters |
|---|---|
| Length, width and height of each packed piece | Decides the equipment and the over-width or over-height charges |
| Weight of each piece and its centre of gravity | Decides the cranes, lashing and the container type |
| Drawings or photos with the lifting points | Needed for the stowage and lashing plan |
| Pickup address and loading equipment at the factory | A crane or forklift may need to be hired |
| Destination address and unloading equipment | Oversized trucking and cranes must be arranged at destination too |
| Ready date | Flat racks and open tops must be reserved early |
Packing and Lashing Standards
Heavy and oversized cargo must be packed and secured so it cannot shift at sea. The international reference is the IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units, known as the CTU Code. In practice, this means:
- Steel skids or heavy timber bases, with timber that meets ISPM 15 rules.
- Lashing with chains or rated straps to the container’s lashing points, with enough lashings for the weight.
- Timber blocking and bracing to stop sliding and tipping.
- Waterproof wrapping and rust protection for cargo on open flat racks.
- Photos and, for valuable cargo, a lashing survey before the container leaves.
Oversized Cargo Shipping with JIEYI
We ship machinery, vehicles, steel structures and other oversized cargo from China by flat rack, open top and breakbulk. We can arrange:
- Booking of flat rack and open top containers, and breakbulk space.
- Crating, lashing and securing at the factory or the port.
- Oversized inland transport in China, with the right trailers.
- Export customs clearance, sea freight, and import clearance and delivery at destination.
For vehicles, see also our guide to shipping cars from China, including RoRo shipping. For standard cargo, see sea freight.
FAQ
What is a flat rack container used for?
For cargo that is too wide, too tall or too heavy for a standard container, such as machinery, vehicles, steel structures and large crates. It has a strong floor and end walls, but no roof or side walls.
What is the difference between a flat rack and an open top container?
An open top has full side walls and a removable roof, so it suits tall cargo that fits the container’s width. A flat rack has no side walls, so it can carry cargo wider than a container.
How much does it cost to ship oversized cargo from China?
It depends on the dimensions, weight, route and handling needed. Over-width and over-height cargo is charged for the space it blocks, so every shipment is quoted individually.
Can a flat rack carry cargo wider than the container?
Yes. That is the main reason to use one. The extra width is charged as over-width, and the cargo must be properly secured.
When should I use breakbulk instead of a flat rack?
When a single piece is too large or too heavy even for a flat rack, or when several flat racks together would cost more than shipping the cargo loose in the hold.
Checked on 2 November 2026. Container figures are typical values; exact specifications vary by carrier. Have oversized cargo to ship? Send us the dimensions, weight and photos, and get a quote.
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