Flat Rack Shipping & Containerizing Oversized Machinery: How We Ship What Most Can't
When cargo is too wide, tall, or heavy for a standard box, most forwarders default to expensive breakbulk or walk away. Here is how flat racks, open tops, and strategic dismantling let us containerize machinery others can't.
Seaway Project Cargo Team
Project Cargo & Heavy-Lift Specialists
The single biggest cost lever in heavy-equipment shipping is also the most misunderstood: whether a machine moves as containerized cargo, on flat racks / open tops, or as breakbulk. Many forwarders look at an out-of-gauge (OOG) piece, default to the most expensive option, and pass the cost straight to you — or decline the job entirely. Our work starts one step earlier: can this be engineered to fit a box?
Flat racks and open tops: the out-of-gauge workhorses
A standard 40ft container has an internal door opening of roughly 2.34m wide and 2.28m high. The moment a machine exceeds that, you are in out-of-gauge territory and need specialized equipment:
- Flat rack containers — collapsible-end or fixed-end platforms for cargo that is too wide or too heavy to load through container doors. Loaded by crane or forklift from the top or side, then lashed and chained to ISO lashing points.
- Open-top containers — a standard box with a removable tarpaulin roof, ideal for cargo that is in-gauge in width but over-height, or that must be crane-loaded.
- Platform (20ft/40ft) flats — for very heavy, very long single pieces.
These let cargo keep the handling advantages of containerized shipping — frequent sailings, standardized lashing, easier inland moves — even when it would otherwise be forced into slower, less frequent breakbulk service. See our container space calculator to test how a piece fits before you book.
The capability most forwarders skip: dismantling and containerizing
Here is where we differ. A large share of "oversized" machinery is only oversized as assembled. Dismantled to a sensible knock-down level, it fits standard or high-cube boxes:
- Excavators — remove the boom, arm, and counterweight; the base often fits a flat rack or even a high-cube box, with attachments crated alongside. (More on excavators.)
- Cranes — separate the crawler crane car body, crawlers, boom sections, and counterweights into containerizable modules.
- Drilling and process equipment — break drilling rigs, transformers, and skids into shippable sub-assemblies with a documented reassembly plan.
This is the classic CKD / SKD (completely / semi knocked-down) approach the auto and machinery industries have used for decades, applied to project cargo. Done properly it requires three things many freight forwarders simply don't have in-house: the engineering to plan a safe dismantle/reassemble sequence, the rigging and crating to protect machined surfaces and hydraulics in transit, and the documentation so the consignee (or their OEM technician) can put it back together and preserve the warranty.
When containerizing wins — and when it doesn't
Containerizing is not always the right answer. The decision is a genuine trade-off:
| Factor | Containerize (incl. dismantled) | Flat rack / open top | Breakbulk |
|---|---|---|---|
| Cargo size | Fits a box, or can be knocked down to fit | Modestly over-gauge | Massively over-gauge / indivisible |
| Sailing frequency | Highest | High | Lower, schedule-driven |
| Cargo protection | Best (enclosed) | Good (lashed, tarped) | Exposed, needs robust packing |
| Reassembly cost | Added at destination | None | None |
| Best for | Used equipment, machinery, parts | Single OOG pieces | Indivisible heavy-lift |
The right call depends on the piece, the lane, and the destination's handling capability. A buyer importing a used excavator to a port with limited heavy-lift gear is often far better off with a dismantled, containerized move than waiting on a breakbulk sailing.
How we approach it
- Survey and measure — exact dimensions, weight, and centre of gravity, plus what can safely be removed.
- Engineer the method — containerize (assembled or knocked-down), flat rack, or breakbulk, with a lashing and securing plan.
- Crate and protect — preserve hydraulics, electronics, and machined surfaces.
- Document for reassembly — so the machine arrives ready to be made whole.
If you have a piece you have been told "won't fit a container," that is exactly the conversation we want to have. Explore our project cargo service, browse the equipment we move, or request a quote with your dimensions and we'll tell you honestly whether it boxes, flat-racks, or ships breakbulk.
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