Container ship capacity is measured in twenty-foot equivalent units (TEU). Typical loads are a mix of 20-foot and 40-foot (2-TEU) ISO-standard containers, with the latter predominant.
Today, about 90% of non-bulk cargo worldwide is transported by container, and modern container ships can carry over 19,000 TEU (e.g., MSC Zoe). Container ships now rival crude oil tankers and bulk carriers as the largest commercial vessels on the ocean.
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, on the other hand, are transported in packages, and are generally manufactured goods. Before the advent of containerization in the 1950s, break-bulk items were loaded, lashed, unlashed and unloaded from the ship one piece at a time. However, by grouping cargo into containers, 1,000 to 3,000 cubic feet (28 to 85m3) of cargo, or up to about 64,000 pounds (29,000kg), 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 metric tons worth of cargo.
In UML, containment is depicted with a multiplicity of 1 or 0..n (depending on the issue of ownership), indicating that the data type is composed of an unknown number of instances of the composited data type.
In OOP supported languages, containership means an object is created within another object.