RORO SHIPS

Roll-on/roll-off (RORO or ro-ro) ships are vessels designed to carry wheeled cargo, such as automobiles, trucks, semi-trailer trucks, trailers and railroad cars that are driven on and off the ship on their own wheels. This is in contrast to lo-lo (lift-on/lift-off) vessels which use a crane to load and unload cargo.

RORO vessels have built-in ramps which allow the cargo to be efficiently "rolled on" and "rolled off" the vessel when in port. While smaller ferries that operate across rivers and other short distances often have built-in ramps, the term RORO is generally reserved for larger ocean-going vessels. The ramps and doors may be stern-only, or bow and stern for quick loading.

Various types of RORO vessels include ferries, cruiseferries, cargo ships, and barges. New automobiles that are transported by ship are often moved on a large type of RORO called a Pure Car Carrier (PCC) or Pure Car Truck Carrier (PCTC).

Elsewhere in the shipping industry cargo is normally measured by the metric tonne, but RORO cargo is typically measured in units of 'lanes in metres' (LIMs). This is calculated by multiplying cargo length in metres by the number of decks and by its width in lanes (lane width differs from vessel to vessel and there are several industry standards). Aboard PCCs cargo capacity is often measured in RT or RT43 units based on a 1966 Toyota or in car equivalent units (CEU).

Since 1970 the market for exporting and importing cars has increased dramatically and the number and type of ROROs has increased also. In 1973, Japan’s K Line built European Highway, the first pure car carrier (PCC), which carried 4,200 automobiles. Today’s pure car carriers and their close cousins, the pure car/truck carrier (PCTC) are distinctive ships with a box-like superstructure running the entire length and breadth of the hull, fully enclosing the cargo. They typically have a stern ramp and a side ramp for dual loading of thousands of vehicles (such as cars, trucks, heavy machineries, tracked units, Mafi trailers, loose statics), and extensive automatic fire control systems.