Skip to main content

Container shipping

Page 2 – The container is born

The bad old days

New Zealand depends on the sea. Our major cities are coastal and even today almost 99% of imports and exports (by weight) travel by sea.

The switch from sail to steam ships in the United Kingdom trade from the mid-1880s increased the size of ships, made voyages quicker and delivery times more predictable. But the job of loading and unloading them changed little over the next hundred years.

By the 1960s conventional ships had reached the limits of their technical development. They were faster and more automated, and some carried goods on pallets. But these costly capital investments were being wasted by growing delays in ports, where 60-70% of costs were incurred. Poor industrial relations, congested wharf sheds, unpredictable weather and shortages of rail wagons or trucks were clogging our ports.

Shipping lines had already gained some economies of scale by moving single commodities such as coal, grain or oil in ever-larger bulk carriers and tankers. But that was impossible for the general cargo carriers whose holds were stuffed with items such as frozen meat, dairy products, wool, machinery, chemicals and consumer goods, all requiring careful loading, stowage and discharge. Cases, drums, cartons, boxes, bundles, packages, cans, reels, vehicles … there might be tens of thousands of separate items in a single ship.

So, although ships would change, the real trick was changing the loading system. And that is where the shipping container came in.

A US trucker’s ‘out of the box’ solution

Containers were not a new idea. They had been tried on canals and sea lanes before, but most failed because they weighed almost as much as the cargo they could carry. Worse, they were not interchangeable. Roll-on, roll-off ships worked well for short-sea trades, but vehicles and trailers wasted too much cargo space to work on long-distance routes.

And then along came American trucker Malcolm McLean, who looked at sea transport through a landsman’s eyes. One day while watching a ship loading it occurred to him that they could speed things up by taking the box off a truck chassis and loading it directly onto the ship. After a bit of experimentation, and some non-standard boxes, in 1961 the International Standards Committee accepted US sizes for 10-, 20-, 30- and 40-foot containers. These ‘Series 1 Measurements’ were based on allowable lengths for truck trailers.

McLean’s experience with trucks and trains launched a new interest in ‘intermodalism’ – making cargo movement as seamless as possible between sea and land transport.

There are some non-standard containers for special trades, and the Americans use larger boxes in their internal trades, but the 20-ft long, 8ft wide and 8ft 6in high container, and its 40-ft big brother, dominate international trade. An empty 20-footer weighs about 2.3 tonnes and can hold about 22 tonnes of freight, depending on what is being transported.

As a bonus for shippers, the steel boxes greatly reduced pilfering and damage in transit.

Container lingo

Containers generated new jargon. Because slots are used to hold containers in place on ships, a vessel's capacity is often described in terms of slot capacity. Shipping lines often ‘slot charter’ on other lines’ vessels, much as airlines now code share. Cellular container ships have guide cells in their hulls to secure the corners of containers.

The boxes themselves come in a variety of designs – open top, flats, platforms, ventilated, insulated, tanktainers, reefer and high cube – but the main ones are the 20- and 40-ft general cargo boxes. Thus the term TEU (20 equivalent unit) is often used to describe a ship’s capacity. In traditional style, Columbus New Zealand, for example, had a deadweight (carrying capacity) of 22,266 tons; she also had a TEU of 1211.

No prizes for guessing that empty containers are referred to as MTs.

How to cite this page

The container is born, URL:, (Manatū Taonga — Ministry for Culture and Heritage), updated