PCCs and PCTCs have a multi-story deck structure, like multi-level parking lots. Because their unique hull shape exposes a large area to the wind, they are more susceptible to “leeway,” in which the vessel is pushed by the wind and proceeds at an angle, than other ships. MOL’s car carriers feature rounded bows with a diagonal cut to reduce crosswinds and improve fuel efficiency, and the sides are stepped over the entire length of the vessel to reduce the effects of crosswinds.

Some of the cargo decks are “liftable decks,” which means their height can be adjusted in accordance with vehicle height, so vessels can load not only passenger cars, but also taller vehicles such as buses, trucks, and even large construction machinery. To maximize loading capacity, the drivers leave just 30cm between the front of one car and the rear of the next, and a mere 10cm from side to side.

In the days of the Oppama Maru, car carriers could hold about 1,200 vehicles, but current PCCs and PCTCs have capacities of up to 8,500 units. Loading capacity is calculated for standard passenger cars measuring 4.125m long and 1.55m wide. MOL’s FLEXIE series vessels, delivered in 2018, have capacities of 6,800 units, and can flexibly accommodate a wide variety of vehicles. They have 14 decks, six of which are height-adjustable, and can load cargo as tall as 5.6m. And the rampway can hold cargo weighing up to 150 tons. These modern vessels can transport virtually any type of vehicle and a range of other self-propelled cargoes as well.

Containerships call at dedicated terminals that have container loading and unloading facilities and equipment. So generally, these vessels are not equipped with onboard cranes. Vertical rails called “cell guides” are installed in cargo holds to load containers efficiently, and the containers are lashed to keep them in place. “Lashing bridges” serve as scaffolds for lashing operations on deck. In addition, containerships can sail at higher speeds than other ship types to maintain stable calling schedules.

Shipping containers, which were introduced in the 1950s, had a massive impact on the trade and transport of commodities and products, not to mention the development of global supply chains. At the time, ocean cargo transport depended mainly on labor-intensive and inefficient cargo loading processes. In fact, labor costs accounted for the majority of logistics expenses. However, the use of standardized shipping containers has made it possible to transport large quantities of miscellaneous goods safely and inexpensively.