Flat Rack Container Shipping: When and Why You'd Use One

A flat rack container is essentially a reinforced steel base or platform with collapsible end walls but no sides or roof, designed to carry cargo that exceeds the dimensions of a standard enclosed container. Unlike a box container, where cargo is loaded through end doors and fully enclosed, a flat rack is loaded from above or the side using a crane, and the cargo is then secured directly to the platform's lashing points with chains, straps and timber blocking.

Flat racks come in standard 20ft and 40ft lengths, matching the footprint of conventional containers so they stack and handle normally within a vessel's cell guides, but because there's no roof or sides, cargo can overhang the width and height limits of a standard container within the vessel operator's approved tolerances, making them suitable for genuinely oversized loads that simply wouldn't fit inside a box.

For the vast majority of cars, a flat rack is unnecessary and a standard container or RORO booking is both cheaper and more protective. Flat racks earn their place for genuinely oversized vehicles — full-size motorhomes and coach conversions that exceed standard container internal height, agricultural and construction machinery, commercial trucks and buses, and certain modified or lifted vehicles that no longer fit within standard height or width tolerances.

They're also occasionally used for non-running vehicles being shipped to a destination with no viable RORO service and where the vehicle's dimensions or condition make loading into a standard container impractical — for example, a vehicle with a badly damaged suspension that can't be safely driven onto a container ramp but can be lifted by crane directly onto a flat rack instead.

The defining trade-off with a flat rack is exposure. Because there are no sides, roof or enclosure, cargo on a flat rack is exposed to weather, sea spray and the general elements throughout the voyage in much the same way as a vehicle on an open RORO deck, and sometimes more so if the flat rack is stowed on an exposed upper deck position on the vessel rather than below decks. This makes proper weatherproofing, corrosion inhibitor application and secure covering (where the carrier permits it) considerably more important than for an enclosed container shipment.

Securing quality also matters enormously and is entirely dependent on the loading team's competence, since there's no container structure providing any inherent restraint — everything relies on chains, turnbuckles, timber chocking and correctly rated lashing points. We only use loading teams with specific experience in vehicle and machinery flat rack lashing, because poor securing on a flat rack is one of the more common causes of cargo shift damage industry-wide, precisely because it's a less forgiving method than an enclosed container if done poorly.

Flat rack shipping is generally more expensive than standard container or RORO shipping for an equivalent-value cargo, both because of the specialist crane loading required at both ends of the voyage and because the shipping line typically charges a premium for the deck space a flat rack consumes, since it can't be stacked as densely as standard containers. For a large motorhome or piece of machinery, expect flat rack costs to run from roughly £2,500 to £5,000+ depending on dimensions, weight and route, noticeably above standard container equivalents.

Availability is also more limited than standard equipment — not every vessel or route carries flat rack capacity, and bookings often need to be made further in advance, typically 4 to 8 weeks ahead of the intended sailing, to secure both the equipment and appropriate crane-lift port slots at both origin and destination.

Start by checking your vehicle or machine's exact dimensions and weight against standard container internal limits (roughly 2.35m wide, 2.39m high for a standard container, or 2.69m high for a high-cube) and against RORO deck height clearances at your intended port (commonly 2.5–3m). If your cargo exceeds these on any dimension, or its weight exceeds standard axle or deck load limits, a flat rack becomes the realistic option rather than a preference.

If your vehicle does fit within standard limits, a flat rack rarely makes sense given the added cost and reduced weather protection — RORO or a standard container will almost always be the better choice. We always check actual dimensions against the available equipment and routes before recommending a flat rack, since it's a specialist solution for a specific problem rather than a general-purpose shipping method, and getting this assessment wrong either wastes money unnecessarily or, worse, results in a booking that has to be changed at short notice once the vehicle turns out not to fit.