Roll-on/roll-off (RORO or ro-ro) ships are vessels designed to carry wheeled cargo such as automobiles, trucks, semi-trailer trucks, trailers or railroad cars that're driven on and off the ship on their own wheels. This's 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… (More on Roro)