Most cargo damage happens inside a container that was never opened in transit. The goods were fine when the doors closed and wrecked when they opened, because nothing stopped them moving. A container at sea rolls, pitches and slams; on road and rail it brakes and jolts. Cargo that is not secured travels the whole way.
General guidance. The internationally recognised reference is the IMO/ILO/UNECE Code of Practice for Packing of Cargo Transport Units, the CTU Code, which your forwarder or packer should be working to. Specific cargo may need engineered securing.
Weight distribution first
Before securing anything, get the load balanced. Two rules do most of the work:
- Distribute weight evenly along the floor. Concentrating heavy cargo at one end overloads an axle when the container is on a chassis, which can make it undeliverable by road even though the total weight is legal. See weight limits.
- Heavy at the bottom, light on top. Obvious, routinely violated when loading is rushed, and the direct cause of crushed lower cartons.
Side to side matters as much as front to back. A container loaded heavy on one side rolls badly at sea and is a genuine safety problem for whoever opens it.
Fill the voids
Empty space is what lets cargo move, so the goal is a load that cannot shift because there is nowhere to shift to. In order of preference:
- Plan the stow so gaps do not exist: carton and pallet dimensions that divide into the container. Check with the cartons per container calculator and the pallet calculator.
- Fill remaining gaps with dunnage bags, airbags, honeycomb board or timber bracing.
- Block and brace at the door end, which is where movement concentrates and where damage shows first.
Do not leave the last metre loose. The most common single failure is a well-packed container with a gap at the doors, so the whole load walks backwards over a five-week voyage.
Lashing and restraint
For anything heavy, wheeled or unable to be blocked in (machinery, vehicles, drums, coils) friction alone is not restraint. Use the lashing points built into the container, rated webbing or chain appropriate to the weight, and secure in all four directions, not just fore and aft. Cargo shifts sideways too.
Two things worth confirming with whoever packs:
- Lashing points have a working load limit. Overloading them is the same as not lashing at all.
- Edge protection under straps, or the strap cuts into the cargo and loosens as the load settles.
Moisture: the damage nobody plans for
Container rain is real. Warm moist air sealed in with the cargo condenses on the roof as the container passes through temperature changes, then drips back onto the goods. It ruins paper, board, textiles, electronics and anything hygroscopic, and it looks exactly like water ingress from outside.
Mitigations, in rough order of cost:
- Desiccant: hanging bags or pole units sized to the container and voyage length.
- Kraft or barrier liners between cargo and container walls.
- Do not load damp goods or wet pallets. The moisture you seal in is the moisture that condenses.
- Avoid direct contact with the walls and floor, which are the coldest surfaces.
Before the doors close
- Photograph the stow: loaded, braced, and with the doors open before sealing. This is the single most useful evidence in a claim.
- Record the seal number and check it matches the documents. A high-security seal is standard on international moves.
- Confirm the verified gross mass: the SOLAS declaration is mandatory and an incorrect one stops the container. Use the VGM calculator.
- Check the container itself before loading: holes, previous cargo residue, odour, damaged floor. Reject a bad box; you inherit its problems.
- Match the piece count to the packing list exactly.
Why this is worth your attention rather than your supplier's
Packing is usually done by the supplier or a packer you never meet, and the consequences land on you. Carrier liability is limited by weight rather than value and will not cover a damaged consignment. See cargo insurance. Worse, insurers and carriers both decline claims where the cause was inadequate packing or securing, which is a category the shipper owns.
So specify securing requirements in writing alongside your packaging specification, and ask for the photographs. Export packaging and palletisation covers the carton and pallet side, supplier cargo readiness covers the pre-shipment checks, and how to file a cargo claim covers what happens when it still goes wrong.
For out-of-gauge and heavy items, securing becomes an engineering exercise. See project cargo and out-of-gauge shipping.
Find forwarders who supervise loading at origin, or post a request.
