Open-Top / Hard-Top / Flat-Rack Containers: Special Container Solutions for Over-Height and Over-Weight Cargo

When cargo exceeds the internal dimensions or weight limits of a standard dry container, special containers are needed. Open-top, hard-top, and flat-rack containers are the three most common solutions for out-of-gauge cargo.

Want to compare standard container types? See the Dry Container (20GP/40GP/40HQ) Guide; for other special container types, see Special Container Introduction, and for temperature-controlled cargo, see Reefer Container Guide.

1. Core Parameter Comparison of Three Container Types

2. Open Top Container

Applicable Scenarios

The top of an open top container is covered with a waterproof tarpaulin, allowing cargo to be loaded and unloaded from above. Suitable foroverheight cargo that does not exceed the height of the container frame.

Suitable cargo types:

• Cargo with height exceeding the standard container door (>2,280mm) but not exceeding 2.3m
• Equipment that needs to be lifted from above
• Large glass and stone slabs
• Long steel pipes, long timber (may protrude outside the container, but must be handled as out-of-gauge)

Usage Method

Open top container loading procedure:
1. Open the tarpaulin cover → remove the arch beams → open the top
2. Use a crane to lower the cargo into the container from above
3. Position the cargo → secure/lash
4. Install the arch beams → cover with tarpaulin → lash and secure the tarpaulin

Open Top Container Fees

3. Hard Top Container

Applicable Scenarios

Hard top containers are similar to open top containers, but the top cover is a removable steel structure rather than canvas. Suitable forscenarios where load-bearing above the cargo is required.

Key differences from open top containers:

Suitable cargo:

• Over-height cargo requiring rigid protection from above
• Return shipment scenarios where empty containers need to be stacked
• Over-height mechanical equipment

4. Flat Rack Container

Applicable Scenarios

Flat rack containers have no side walls or roof, only a floor base and two end walls, allowing loading/unloading from any direction. They are suitable foroverweight, oversized, and irregularly shaped cargo.

Suitable cargo types:

Key Points for Using Flat Rack Containers

Lashing Ring Distribution on Flat Rack Containers

Schematic of lashing rings on a 20ft flat rack container (floor plan view):
┌──────────────────────────────────────┐
│ ○──○──○──────────────○──○──○  │ ← Lashing rings on both sides
│ │                                  │
│ │                                  │
│ ○──○──○──────────────○──○──○  │
└──────────────────────────────────────┘
  About 6-8 lashing rings on each side, load capacity ≥2,000kg each

5. Type Selection Decision Process

Cargo exceeds standard container limits?
    │
    ├── Only overheight (>2.3m) → Open-top container
    │
    ├── Overheight + requires stacking → Hard-top container (rarely used, order in advance)
    │
    ├── Overweight (>28 tons) or irregular shape → Platform container
    │
    └── Overlength (>12m) → Platform container (over-limit declaration)
            │
            └── Overlength >15m → Charter vessel (flat rack container not enough either)

6. Cost Comparison of Three Container Types (Reference)

The above surcharges do not include over-limit operation fees, lashing fees, or special terminal handling fees. The actual total cost must be confirmed per shipment.

7. Booking Precautions

Data Notes: The fee reference is an industry-wide estimate; actual fees are affected by shipping route, container availability, and terminal handling charges. It is recommended to confirm special container usage fees with the shipping line on a per-shipment basis.Data as of July 2026.

Do you have over-height or over-weight cargo that needs sea freight? Send us the cargo drawings and dimensions, and Bofeng Logistics will help you choose the most cost-effective out-of-gauge cargo shipping solution.

Out-of-Gauge Cargo Consultation: 13075678958 | info@zhbfwl.com

Special Container FAQ

Q: How to choose between open-top and flat-rack containers?

A: For cargo whose height only slightly exceeds a standard container and needs top lifting, choose an open-top container; for overweight, oversized, or irregularly shaped cargo that needs free loading and unloading from the side and top, choose a flat-rack container.

Q: How far in advance should special container bookings be made?

A: Shipping lines have limited configurations for special containers and demand is low, so it is recommended to book 2-3 weeks in advance and provide cargo drawings, dimensions, weight, center of gravity position, and loading/unloading methods so the shipping line can review the lashing plan.

Disclaimer: This article was compiled and written by the Bofeng Logistics team, with content verified in August 2026. Container parameters and cost data may be adjusted due to changes in shipping lines, routes, and market conditions; please refer to the information confirmed at the time of booking.