Quick Answer: A flat rack container is a steel platform with two end walls and no sides or roof, used when cargo is too wide, tall or heavy for a standard dry box. Its payload depends on the specific unit, and it loads by crane from above or the side.
- Flat racks exist for one reason: your cargo breaks the walls, roof or door opening of a standard 20ft or 40ft dry container.
- Flat rack payloads vary by size and model; check the rating for the exact unit assigned to your booking.
- Pricing is slot-based: every meter of overwidth or overheight blocks neighboring slots, and the carrier bills those lost slots plus lift-on/lift-off and lashing.
- Book OOG cargo well ahead of the sailing — the carrier must approve the out-of-gauge booking before the vessel stowage plan closes.
Flat rack container shipping sits between normal FCL and full breakbulk. You keep container-vessel schedules and container paperwork, but the cargo, the lashing and the price behave like project cargo.
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Go to the calculator →Reference prices: container shipping from Miami
| Destination | 20 ft container | 40 ft HC container | Transit |
|---|---|---|---|
| El SalvadorAcajutla | $2,465 | $2,807 | 26 days |
| HondurasPuerto Cortes | $2,639 | $3,287 | 21 days |
| GuatemalaSanto Tomas de Castilla | $1,847 | $2,203 | 27 days |
| Dominican RepublicCaucedo | $1,431 | $1,728 | 12 days |
| ColombiaCartagena Colombia | $810 | $972 | 12 days |
| PanamaRodman | $1,080 | $1,296 | 21 days |
| PeruCallao | $1,080 | $1,296 | 19 days |
| EcuadorGuayaquil | $1,080 | $1,296 | 17 days |
Port-to-port rates in USD from Port Everglades, calculated with our quoting system (current since September 28, 2026). 20 ft container: general cargo. 40 ft HC container: general cargo. They include freight and US export charges; they do not include import taxes or local charges at destination. The calculator on this page gives your exact price, with pickup and delivery.
What Is a Flat Rack Container Used For?
Quick Answer: A flat rack container is an ISO-standard steel base with two fixed or collapsible end walls, no sides and no roof. Carriers use it for cargo that cannot pass through a dry container door: excavators, transformers, boats, pipe bundles, pressure vessels and prefabricated steel sections loaded by crane from above.
The equipment itself is simple. A reinforced steel deck sits on standard ISO corner castings, with two end walls and nothing else. Lashing rings run along both deck rails, each with a load rating that depends on the manufacturer.
That open design unlocks three loading methods a dry box cannot offer.
- Overhead crane: the terminal gantry or a mobile harbor crane lowers the unit straight onto the deck
- Side-load by forklift: useful for pipe bundles, steel coils and crated machinery at inland plants
- Roll-on from a low-bed trailer: tracked and wheeled units drive across a ramp onto the deck
What cargo moves on flat racks from US gateways?
The pattern repeats across every lane we handle. Caterpillar and John Deere units leave Houston for Central and South America almost weekly. Power transformers move out of Savannah. Sportfishers and yachts load at PortMiami for the Caribbean and Colombia.
Mining equipment headed to Peru and Chile usually books through Los Angeles/Long Beach. Midwest shippers rail their machinery to Chicago, then on to a coastal gateway. Canadian exporters use Toronto, Montreal or Vancouver depending on province.
One structural point matters for planning. A flat rack is container equipment, not breakbulk. It rides a container vessel, keeps the container sailing schedule and travels under a standard ocean Bill of Lading — not a breakbulk charter party.
Pro Tip
RVs, motorhomes, semi-trucks and large machinery never fit inside a container. They move on a flat rack or a RoRo vessel, and a project cargo specialist quotes them after reviewing dimensions. Send the drawings first — guessing the equipment type wastes two weeks.
What Is Out-of-Gauge (OOG) Cargo and How Is It Measured?
Quick Answer: Out-of-gauge cargo is any load that exceeds the internal dimensions of a standard container in at least one direction. Carriers measure it three ways: overwidth beyond the flat rack deck edge, overheight above the end walls, and overlength past the corner castings — each measured in centimeters per side.
Every carrier OOG desk wants the same three numbers. Get them right and the booking moves. Get them wrong and the stowage planner rejects the unit at the terminal gate.
Overwidth, overheight and overlength explained
Overwidth is measured left and right of the deck centerline, separately. Anything past the deck edge intrudes into the adjacent container slot. A machine 80 cm wider on each side blocks slots on both sides of the vessel bay.
Overheight is measured from the deck surface, not from the ground. Anything above the top of the end walls counts as overheight and prevents stacking a container on top.
Overlength is the hardest to place. Carriers limit how far cargo may overhang each end, and the limit varies by carrier. Longer pieces move to a 40ft rack, or onto two flat racks coupled as a bolster arrangement with the load bridging both decks.
In-gauge loading on a flat rack is also possible. If your machine fits inside the end walls and stays within the deck edges, you pay no OOG surcharge at all. You still pay the flat rack equipment rate, but the slot-loss math disappears.
Weight distribution fails bookings more often than width
Dimensions get the attention, but point loads sink approvals. Heavy contact points and axles need load-spreading timber bearers; ask the carrier for the deck's load limits. Skip the dunnage and the deck plate deforms — the carrier then bills you for container damage on top of the freight.
What Are the Dimensions of a 20ft and 40ft Flat Rack Container?
Quick Answer: Flat rack dimensions and payloads vary by size, type and manufacturer. A 40ft unit gives a much longer deck than a 20ft unit, and high-capacity models carry heavier loads. Confirm the exact figures for the unit assigned to your booking with the carrier.
The 40ft flat rack dimensions matter most for machinery exporters, because the usable height drops as the deck gets stronger. A heavier deck structure sits higher off the ground, which steals end-wall clearance.
Flat rack payload by equipment type
See the data
| Equipment | Max payload | Usable deck length | ISO type code |
|---|---|---|---|
| 20ft flat rack (collapsible) | 30,000 kg | 5.65 m | 22P1 |
| 20ft flat rack (fixed end) | 34,000 kg | 5.70 m | 22P3 |
| 40ft flat rack (collapsible) | 40,000 kg | 11.80 m | 42P1 |
| 40ft high-capacity flat rack | 45,000 kg | 12.00 m | 45P3 |
Source: ISO 6346 type codes and published carrier equipment specifications (Maersk, MSC, Hapag-Lloyd) · January 2026
Why tare weight decides your inland leg
A 40ft HC flat rack carries substantial tare weight of its own. That steel counts against your road-legal gross weight long before the box reaches the port.
US federal interstate limits cap gross combination weight at 80,000 lb (about 36,287 kg) without permits. Add a 15,000 kg machine to the rack's tare and a chassis, and the math gets tight fast. Over-dimensional and overweight permits follow, state by state.
Collapsible, fixed-end and platform containers
Collapsible flat racks fold their end walls flat for repositioning. Carriers stock more of them because an empty stack of folded racks occupies one container slot instead of four. The trade-off: folding end walls carry lower lashing loads than welded fixed ends.
Platform containers — sometimes called flat beds — have no end walls at all. They suit very long, low cargo such as rail sections, pipe strings and structural steel. Availability is thin outside major gateways.
Compare that with a standard 40ft dry container's payload limit — payload is the single biggest reason heavy machinery books a flat rack even when it would fit inside a box dimensionally.
What Is the Difference Between a Flat Rack and an Open Top Container?
Quick Answer: An open top container has four walls and a removable tarpaulin roof; a flat rack has no sides at all. Choose open top when your cargo is overheight but fits inside the box's internal width. Choose a flat rack when the cargo is overwidth, overlength, or needs side or crane loading.
The decision rule fits on one line. Too tall only equals open top. Too wide, too long or too heavy equals flat rack.
Open Top Container
Four solid walls, a removable roof bow and a tarpaulin. Cargo loads through the top by crane but stays inside the container footprint. The tarp gives real weather protection, and the box stows in the hold like a normal container when the overheight is modest.
Flat Rack Container
Open deck, two end walls, no roof. Cargo can overhang in any direction and load from the side or the top. Almost always stowed on deck, so it takes salt spray, UV and rain. Payload reaches 45,000 kg on a 40ft high-capacity unit — the choice for heavy machinery.
| Equipment | Internal width | Max payload | Loading method | Best-use cargo |
|---|---|---|---|---|
| Standard 40ft dry | Varies by unit | Varies by unit | Through rear doors | Palletized and crated goods |
| 40ft open top | Varies by unit | Varies by unit | Top crane, rear doors | Tall crates, tanks, glass panels |
| 40ft HC flat rack | Varies by unit | Varies by unit | Crane, side forklift, roll-on | Excavators, transformers, boats |
| 40ft platform | Varies by unit | Varies by unit | Crane, side load | Rail sections, long pipe, steel |
At destination, the handling difference shows up again. A standard box discharges and unloads on a dock in a few hours — see How Long to Unload a 40ft Container: 2-8 Hours for realistic timings. A flat rack needs a crane or heavy forklift waiting at the consignee's site, which you must arrange before the vessel arrives.
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Go to the calculator →How Much Does It Cost to Ship a Flat Rack Container?
Quick Answer: Flat rack container shipping is priced by slots, not by box. Carriers charge the base flat rack rate plus every container slot your overwidth or overheight blocks, then add lift-on/lift-off, lashing and securing, and an OOG handling fee at both terminals. Dimensions drive the number more than weight does.
What is slot loss and why does it dominate the price?
A container vessel sells space in slots. When your cargo overhangs a flat rack, the slots next to it, or above it, cannot take another container. The carrier bills you for that lost revenue.
Overwidth on both sides doubles the count. A machine 60 cm over on the left and 60 cm over on the right can block two adjacent slots per tier. Overheight above the end walls kills the slot directly on top. Carriers publish their out-of-gauge handling rules — Maersk's out-of-gauge cargo guidance explains how overhang is assessed before booking approval.
As a working benchmark across the USA–Latin America corridor, a 40ft flat rack commonly prices at 1.5 to 3 times a standard 40ft rate on the same lane — before lashing, crane and permit costs land.
The full cost stack
- Base flat rack equipment rate for the lane
- Slot loss charges, counted per blocked slot
- Lift-on/lift-off at origin and destination terminals
- Lashing materials and labor (chains, turnbuckles, timber, rubber mats)
- Independent surveyor fee where the carrier requires one
- On-deck stowage premium
- Origin THC and destination THC (DTHC)
- BAF, CAF and peak season surcharge where applicable
The inland US leg is a separate budget line
Getting an over-dimensional machine from your plant to the port is its own project. Expect a low-bed or step-deck trailer, state-by-state over-dimensional permits, and escort vehicles on wide or tall loads.
In Texas, the TxDMV requires a company-certified route inspection before issuing a permit only when the load is taller than 18'11", wider than 20' or longer than 125'. That inspection checks bridge clearances, overhead utility lines and turning radii. Permit rules and timing vary by state, so confirm them with each state before you schedule the move.
How your gateway changes the quote
Origin gateway drives both price and transit. Florida ships through PortMiami. Texas and the central states route via Port Houston. California and the Southwest use Los Angeles/Long Beach.
The Northeast loads at New York/New Jersey, the Southeast at Savannah, and the Midwest rails through Chicago to a coastal port. Ontario works through Toronto, Quebec and the Atlantic provinces through Montreal, and Western Canada through Vancouver.
HoustonUSHOU
CartagenaCOCTA
Los AngelesUSLAX
CallaoPECLL
Pro Tip: shave 20 cm and save a slot
Before you accept an OOG quote, ask your engineering team what can come off. Removing a boom, a cab, a stack or a set of mirrors often pulls the unit back inside the deck edge. Dropping from overwidth to in-gauge can erase the entire slot-loss charge — the biggest single line on most flat rack invoices.
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Go to the calculator →How Do You Book Flat Rack Shipping from the USA?
Quick Answer: Book OOG cargo well ahead of the sailing. You send the carrier the unit's dimensions, gross weight and the other details it asks for. The carrier reviews and approves the out-of-gauge booking, then assigns a deck position before the vessel's cut-off. Requirements vary by carrier, so ask yours what it needs.
- Submit the unit's dimensions with the drawings and photographs the carrier requests.
- Declare gross weight, center of gravity and certified lifting points.
- Wait for carrier OOG approval before moving the cargo.
- Release the equipment and position the flat rack at the plant or terminal.
- Move the cargo inland with over-dimensional permits and escorts if required.
- Lash the unit at the terminal under the carrier's securing manual.
- Collect the lashing certificate from the terminal or surveyor.
- Issue the Bill of Lading and check that it matches the booking details.
Transit planning follows normal container schedules once the unit is aboard. Short Central American lanes run fast — our breakdown of shipping times from the USA to El Salvador shows how little ocean time a Gulf or West Coast departure actually needs. Longer South American runs behave differently; see how long shipping from the USA to Chile takes before you promise a delivery date.
Equipment availability varies by lane
Flat racks are not evenly distributed. Houston and Los Angeles hold deep flat rack inventory because machinery exports feed the pool. Savannah and inland rail ramps run tighter, and Canadian ramps tighter still in winter.
Book the equipment release early. A confirmed OOG approval means nothing if no rack is available in the yard that week.
Port cut-off and vessel ETD are not the same date
OOG bookings can close earlier than in-gauge containers on the same sailing — confirm the OOG cut-off with the carrier. The stowage planner must fix the deck position before general cargo loads. Miss the OOG cut-off and your flat rack rolls to the next vessel — which on a biweekly LatAm string can mean two lost weeks plus storage at the terminal.
How Do You Secure Cargo on a Flat Rack Container?
Quick Answer: Cargo on a flat rack is secured with chains, turnbuckles, webbing and timber dunnage attached to the deck lashing rings, following the IMO/ILO/UNECE CTU Code and the IMO CSS Code. Ask the carrier whether it requires an inspection and lashing certificate from the terminal or an independent surveyor before loading.
Three documents govern the work. The CTU Code covers packing and securing of cargo transport units. The IMO CSS Code sets out guidance on stowing and securing cargo against the ship's motion. Each carrier then layers its own lashing manual on top.
What hardware a proper lashing job uses
- Lashing chains rated for the weight of the machinery
- Ratchet turnbuckles to tension each chain to spec
- Timber bearers to spread point loads across the deck plate
- Anti-slip rubber mats under steel contact surfaces
- Welded steel stoppers for steel-on-steel cargo that cannot grip
Where the carrier requires a lashing certificate, treat it as a real shipping document, not paperwork theater. Insurers read it first when a claim lands after a heavy-weather passage.
On-deck stowage means weather exposure
Flat racks ride on deck. Salt spray, rain and UV reach the cargo for the whole voyage. Plan protection into the packing spec: shrink-wrap, VCI film for bare steel, desiccant bags inside enclosures and marine-grade tarps over sensitive assemblies.
Common mistake: lashing to the machine's tie-down eyes
Many operators chain to the small tie-down eyes on bodywork instead of the chassis frame. Ocean forces are far higher than road forces. The eyes tear, the sheet metal bends, and the manufacturer voids the warranty on the damage. Always lash to the structural frame and confirm the lifting and lashing points with the OEM drawing.
Flat Rack vs Breakbulk vs RoRo: Which One Fits Your Cargo?
Quick Answer: Flat racks suit OOG cargo up to about 45,000 kg on container-vessel schedules. Breakbulk and heavy-lift charters handle anything heavier or truly massive but sail less often. RoRo wins for self-propelled or wheeled units that can be driven or towed aboard, with no lashing-to-deck complexity.
| Method | Practical weight limit | Sailing frequency | Handling needs | Key document |
|---|---|---|---|---|
| Flat rack | Up to ~45,000 kg | Weekly container service | Crane lift + lashing | Ocean B/L + lashing certificate |
| RoRo | Varies by vessel and carrier | Varies by lane | Drive or tow aboard | B/L + title documents for vehicles |
| Breakbulk | Beyond flat rack limits | Less frequent than container services | Ship's gear or shore crane | Breakbulk B/L + stowage plan |
| Heavy-lift charter | 250,000 kg+ | Chartered per project | Heavy-lift vessel cranes | Charter party + marine survey |
When flat rack wins
Schedule. Container services from PortMiami, Port Houston and Los Angeles/Long Beach sail weekly to Cartagena, Puerto Cortés, Caucedo, Callao and Manzanillo. Breakbulk on the same lanes may sail monthly, or only when a project charter fills. For a single excavator or transformer, the flat rack usually lands weeks earlier.
When RoRo wins
Wheels. Excavators on tires, tractors, buses, motorhomes and trucks drive or tow aboard. No crane lift means no lifting-point engineering and no lashing certificate for the lift itself. RoRo also handles units that exceed flat rack payload. The trade-off: fewer ports and no weather protection whatsoever.
Breakbulk takes over at the threshold. Once a single piece exceeds what the carrier's flat racks can take, the flat rack stops being the answer and a heavy-lift vessel is the right tool.
For in-gauge vehicles the math flips completely. Two sedans share one 40ft box and move as ordinary FCL — our two cars in a 40ft container calculator shows how that loading works against the OOG route a single piece of machinery requires.
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Go to the calculator →Which Incoterms and Insurance Work Best for OOG Shipments?
Quick Answer: FCA and CIP are often preferred to FOB and CIF for flat rack cargo, because risk transfer at the vessel is hard to pin down for crane-lifted units; confirm the right rule for your contract with a trade advisor. Named-perils cover is thin for on-deck carriage, so buy Institute Cargo Clauses (A) with an on-deck extension.
Why FOB and CIF create gaps on OOG cargo
With FOB and CIF, check exactly where your contract places the transfer of risk. For a crane-lifted flat rack, that moment is murky. The lashing happens on the quay, hours or days before loading, and nobody's Incoterm clearly owns it.
With FCA, name the delivery point precisely, such as the terminal where OOG cargo actually changes hands. With CIP, require insurance under ICC (A) in the contract — the broad cover OOG cargo needs. These are the rules the ICC designed for container and multimodal movement.
On-deck carriage and your cargo policy
Flat racks almost always stow on deck. Check whether the Bill of Lading carries an "on deck at shipper's risk" clause. A standard ICC (C) named-perils policy may not respond to washing overboard or sea-water damage in that position.
Buy ICC (A) with an explicit on-deck extension. Confirm the wording with your broker before the vessel sails, not after.
Who pays for lashing?
Don't assume your Incoterm settles who pays for lashing, or that the ocean rate includes it. Write it into the sales contract by name — "securing and lashing at origin terminal for seller's account" — or expect an argument at invoice time.
DDP, DAP and import-side exposure
DDP looks clean on a quote sheet and punishes the seller in practice. You become responsible for import clearance in Colombia, Peru or Mexico. Machinery imports can involve local requirements and registrations a foreign seller may not hold; confirm them with a licensed customs broker in the destination country before shipping.
DAP shifts clearance to the buyer, who already holds the local tax registration — RUT/NIT in Colombia, RUC with SUNAT in Peru, RFC in Mexico — and the broker relationship. For machinery into LatAm, DAP is almost always the safer structure.
Documents that travel with an OOG booking
- Commercial Invoice (Factura Comercial) with full HS classification
- Packing List showing dimensions and weight per piece
- Certificate of Origin (Certificado de Origen) where a trade agreement applies
- Lashing certificate from the terminal or independent surveyor
- ISF 10+2 filing for US imports, 24 hours before vessel loading at origin
- Carrier OOG approval number referenced on the booking
Pro Tip: confirm the HS heading before the vessel sails
Machinery classification drives duty rates at DIAN, SUNAT, SAT and Receita Federal, and a wrong heading triggers inspection and demurrage at destination. Get a licensed customs broker in the destination country to confirm the heading in writing before loading. AB Group Shipping is a freight forwarder, not legal counsel — duty and tax rulings belong with a licensed broker or trade attorney.
Get Your Flat Rack Shipment Priced
Quick Answer: Flat rack container shipping is priced per cargo, not per box. Send dimensions (L × W × H), gross weight, lifting points and your origin city with the destination port. A project cargo specialist returns a quote covering ocean freight, slot loss, lashing, lifts and the inland over-dimensional move.
With thousands of shipments processed across the USA–Latin America corridor, the pattern holds: the shippers who send drawings and real weights on day one sail three weeks sooner than the ones who send a rough description. Measure the widest point, the tallest point and the longest point, then photograph the unit from four angles.
Use the request form on this page to submit your flat rack or OOG cargo. Give us the dimensions, the weight and the lane — Houston to Puerto Cortés, Los Angeles to Callao, Savannah to Santos, Miami to Cartagena or Toronto to Kingston — and a project cargo specialist prices the exact move, including the gateway your region ships through.
Request your OOG quote
Send dimensions and weight — a project cargo specialist prices your exact flat rack move.
Go to the request form →Payload depends on the flat rack's size and type and on the carrier's equipment specification stamped on the CSC plate, with high-capacity 40ft units carrying the most. Always verify the exact payload for the unit assigned to your booking, because older racks carry lower ratings. Road-legal weight limits on the US inland leg are usually the tighter constraint.
Flat rack pricing depends on your origin gateway, the destination port, and how many neighboring container slots your overwidth or overheight blocks — slot loss often costs more than the base freight. Lift-on/lift-off, lashing labor, surveyor fees and over-dimensional road permits add to the total. Submit your dimensions and weight through the request form on this page and a project cargo specialist prices the exact move.
An open top container has four solid walls and a removable tarpaulin roof, so it suits cargo that is too tall but still fits the container's internal width. A flat rack has no sides or roof at all, which allows overwidth, overlength and crane or side loading. Flat racks also carry significantly more weight than open tops.
Book well ahead of your target sailing. The carrier must review and approve an out-of-gauge booking before stowage is assigned, and OOG cut-offs can close earlier than the standard container cut-off. Over-dimensional road permits for the inland leg are issued state by state and add their own lead time, so confirm them with each state early.
No — most excavators, semi-trucks, motorhomes and large machinery exceed the internal width or height of a standard dry container and must ship on a flat rack or a RoRo vessel. Smaller wheeled or tracked units sometimes fit inside a 40ft high cube after removing the boom, cab or attachments. Send dimensions through the form on this page and a specialist confirms which method applies.
Sources
We checked the rules and figures in this guide against these sources on November 7, 2026.
- Federal Highway Administration (U.S. DOT): Bridge Formula Weights- FHWA Freight Management and Operations
- Federal Highway Administration (FHWA): Questions and Answers About Vehicle Size and Weight - FHWA Freight Management and Operations
- Texas Department of Motor Vehicles (TxDMV): Route Inspections for Oversize/Overweight Permits
- U.S. Customs and Border Protection: Frequently Asked Questions Importer Security Filing (ISF) November 2018 · 2018-11-26
- International Maritime Organization: IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units (CTU Code)
- SUNAT (Superintendencia Nacional de Aduanas y de Administración Tributaria): Importa Fácil – Preguntas frecuentes
- International Trade Administration (trade.gov): Special Documents Used in Exporting
✓ Fact-checked by AB Group Shipping on November 7, 2026. Prices come from our own rate system. How we check our guides · Spotted an error? [email protected]