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 of lower costs and less risky. These ships were carrying onboard cranes since most port terminals were not equipped to handle containers. They were also relatively slow, with speeds of about 18 to 20 knots and could only carry containers on the converted decks and not in their bellyhold. 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. Usually an extra of two containers in width can be carried above deck than below deck. Cranes were removed from the ship design so that more containers could be carried (cranes remain today on some specialized containerships). The ability of ports to handle cellular containerships ceased to be a major concern with the setting of specialized container terminals around the world. Cellular containerships were also much faster with speeds of 20-24 knots, which would become the speed of reference in containerized shipping.