The humble steel box

In April 1956, a converted oil tanker called the Ideal X left the port of Newark, New Jersey, bound for Houston, Texas. On its deck were fifty-eight large metal boxes, each of which had been lifted directly from the back of a lorry. There was little public interest in the voyage, and few people at the time could have predicted its importance. Yet that modest journey is now widely regarded as the beginning of a transport revolution, one that would reshape ports, cities and the global economy.

To understand why, it helps to know how goods were moved before. For centuries, cargo was carried in what was known as break-bulk form: sacks, barrels, crates and bales of every shape and size, each of which had to be carried on board by hand or lifted in small loads by cranes. Loading and unloading a single ship could take a team of dockworkers a week or more, during which time the vessel earned nothing. Goods were frequently damaged, and theft was so common that some dockworkers regarded a share of the cargo as an informal part of their wages. Transport costs were so high that, for many products, it was simply not worth shipping them across the ocean.

The man behind the Ideal X, Malcolm McLean, was not a shipping expert but the owner of a trucking company. Frustrated by the hours his drivers spent waiting at ports while their loads were transferred to ships, he reasoned that it would be far more efficient to load the entire trailer box onto the vessel. The idea was not completely original, since railway companies and armies had experimented with containers before, but McLean was the first to build a complete system around it, with specially adapted ships, cranes and lorries. Crucially, he understood that the container was not just a box but a new way of organising transport from start to finish.

The new system did not spread overnight. Different companies initially built containers of different sizes, which meant that a box belonging to one firm might not fit on another firm's ship or train. It took more than a decade of negotiation before international standards for container dimensions and fittings were agreed in the late 1960s. Ports, too, had to be transformed. Container ships needed deep water, huge cranes and large areas of flat land where boxes could be stacked. Many traditional docks, squeezed into the centres of old cities, could not provide these, and the shipping trade moved to new terminals, often many kilometres away.

For the dockworkers who had handled cargo by hand, the consequences were severe. Because a container could be lifted on or off a ship in a couple of minutes, a ship that had once needed a week in port could now be unloaded in less than a day by a much smaller workforce. In port after port, tens of thousands of jobs disappeared, and in many cities the closure of the old docks left behind empty warehouses and communities without work. Dockworkers' unions fought hard against the change, and in some places strikes delayed it for years, but they could not prevent it.

For the world economy, however, the effects were enormous. As the cost of shipping fell, it became practical for manufacturers to produce goods in one country using parts made in several others, and to sell them on the other side of the world. Economists still debate how much of the growth in international trade since the 1960s can be credited to the container, as opposed to other factors such as falling tariffs, but few doubt that its contribution was substantial. Today the largest container ships can carry more than twenty thousand standard boxes, and the cost of shipping a single item across an ocean is often so small that it hardly affects what consumers pay.

The container's success has also created new vulnerabilities. Global supply chains now depend on a relatively small number of very large ports and shipping routes, so that a problem in one place can cause delays around the world. This was demonstrated in 2021, when a single large container ship became stuck in the Suez Canal and blocked it for six days. Customs officials, meanwhile, can physically inspect only a tiny proportion of the millions of sealed boxes passing through ports, which makes the system attractive to smugglers. The steel box, it seems, has made the world more connected, and that connection brings risks as well as rewards.