Container ship

A container ship (also called boxship or spelled containership) is a cargo ship that carries all of its load in truck-size intermodal containers, in a technique called containerization. Container ships are a common means of commercial intermodal freight transport and now carry most seagoing non-bulk cargo.

Container ship capacity is measured in twenty-foot equivalent units (TEU). Typical loads are a mix of 20-foot (1-TEU) and 40-foot (2-TEU) ISO-standard containers, with the latter predominant.

Today, about 90% of non-bulk cargo worldwide is transported by container ships, the largest of which, from 2023 onward, can carry over 24,000 TEU.

There are two main types of dry cargo: bulk cargo and break bulk cargo. Bulk cargoes, like grain or coal, are transported unpackaged in the hull of the ship, generally in large volume. Break-bulk cargoes, in contrast, are transported in packages, and are generally manufactured goods.

Before the advent of containerization in the 1950s, break-bulk items required manual loading, lashing, unlashing and unloading from the ship one piece at a time. This stevedoring process became more efficient by grouping cargo into containers, 1,000 to 3,000 cubic feet (28 to 85 m³) of cargo, or up to about 64,000 pounds (29,000 kg), is moved at once and each container is secured to the ship once in a standardized way. Containerization has increased the efficiency of moving traditional break-bulk cargoes significantly, reducing shipping time by 84% and costs by 35%. In 2001, more than 90% of world trade in non-bulk goods was transported in ISO containers. In 2009, almost one quarter of the world's dry cargo was shipped by container, an estimated 125 million TEU or 1.19 billion tonnes worth of cargo.

The first ships designed to carry standardized load units were used in the late 18th century in England. In 1766 James Brindley designed the box boat "Starvationer" with 10 wooden containers, to transport coal from Worsley Delph to Manchester via the Bridgewater Canal. Before the Second World War, the first container ships were used to carry the baggage of the luxury passenger train from London to Paris (Southern Railway's Golden Arrow / La Flèche d'Or). These containers were loaded in London or Paris, and carried to ports of Dover or Calais on flat cars. In February 1931, the first container ship in the world was launched; the Autocarrier, owned by the Southern Railway. It had 21 slots for containers of Southern Railway.

The earliest container ships after the Second World War were converted oil tankers, built up from surplus T2 tankers after World War II. In 1951, the first purpose-built container vessels began operating in Denmark, and between Seattle and Alaska. The first commercially successful container ship was Ideal X, a T2 tanker, owned by Malcom McLean, which carried 58 metal containers between Newark, New Jersey and Houston, Texas, on its first voyage. In 1955, McLean built his company, McLean Trucking into one of the United States' biggest freighter fleets. In 1955, he purchased the small Pan Atlantic Steamship Company from Waterman Steamship and adapted its ships to carry cargo in large uniform metal containers. On April 26, 1956, the first of these rebuilt container vessels, Ideal X, left the Port Newark in New Jersey and a new revolution in modern shipping resulted.

In the 1950s, a new standardized steel Intermodal container based on specifications from the United States Department of Defense began to revolutionize freight transportation (especially for shipping companies like Seatrain Lines).