Source: Ashar and Rodrigue, 2012. All dimensions are in meters. LOA: Length overall.
- A) Early containerships. The first generation of containerships was composed of modified bulk vessels or tankers that could transport up 1,000 TEUs. The first containership, the "Ideal-X" was a converted World War II T2 tanker. The container was at the beginning of the 1960s an untested transport technology and reconverting existing ships proved out to be the least expensive and risky solution. These ships were carrying onboard cranes since most port terminals were not equipped to handle containers and were relatively slow, with speeds of about 18 to 20 knots. However, they could only carry container on the converted decks. Once the container began to be massively adopted at the beginning of the 1970s, the construction of the first fully cellular containerships (FCC; second generation) entirely dedicated for handling containers started. All containerships are composed of cells lodging containers in stacks of different height depending on the ship capacity. Cellular containership also offer the advantage of using the whole ship to stack containers, including below deck. Cranes were removed from the ship design so that more containers could be carried (cranes remain today on some specialized containerships such as reefers). The ability of ports to handle containership ceased to be a major concern with the setting of specialized container terminals around the world. These ships were also much faster with speeds of 20-24 knots that would become the speed of reference in containerized shipping.
- B) Panamax. Economies of scale rapidly pushed for the construction of larger containerships in the 1980s. The larger the number of containers being carried the lower the costs per TEU. The process became a virtuous circle compounding larger volumes and lower costs. The size limit of the Panama Canal, which came to be known as the panamax standard, was achieved in 1985 with a capacity of about 4,000 TEUs. Once this limit was achieved, a decade passed before a new generation of containerships was designed. At the same time panamax container ship designs were evolving to take maximum advantage of the limitation in beam (Panamax Max). The original dimensions of the Panama Canal, built by the US Army Corps of Engineers, are similar to the dimensions of the US Inland Waterways locks, resulting in a narrow and long ship design.
- C) Post Panamax. Going beyond panamax was perceived as a risk in terms of the configuration of the networks, additional handling infrastructure as well as draft limitations at ports. The APL C10 class containerships were introduced in 1988 and was the first containership class to exceeded the 32.2 m width limit of the Panama Canal. By 1996 full fledged Post Panamax containerships were introduced and capacities reached 6,600 TEUs. A ship above the panamax size requires a substantial amount of cargo to be used profitably along a service loop and by the late 1990s the rapid growth of global trade made such a ship class a marketable proposition. Once the panamax threshold was breached, ship size quickly increased with capacities reaching 8,000 TEUs (Post Panamax Plus; "Sovereign Class"). Post Panamax Containerships require deep water ports (at least 43 feet of draft) and highly efficient, but costly, portainers. This is placing pressures for ports to dredge to accommodate these draft constraints.
- D) New Panamax (NPX). Refers to ships designed to fit exactly in the locks of the expanded Panama Canal, expected to open in 2014, and which confers capacity of about 12,500 TEU. Like its Panamax counterparts, New Panamax ships will compose a specific ship class able to effectively service the Americas and the Caribbean, either from Europe or from Asia.
- E) Post New Panamax. By 2006, a new generation of containerships came online when the maritime shipper Maersk introduced a ship class having a capacity in the range of 11,000 to 14,500 TEUs, the Emma Maersk, (E Class). They are dubbed "Post New Panamax" since these ships are bigger than the expanded Panama Canal specifications and can handle up to about 18,000 TEU (Triple E Class). It remains to be seen which routes and ports these ships would service, but they are limited mostly to routes between Asia and Europe. There are larger ship designs on the drawing boards, such as the "Malacca Max" class that could carry about 27,000-30,000 TEU, but they are not expected to be constructed within a decade.