The vast majority of RoRo shipping takes place using specially designed vessels, mainly catamarans. These are vessels with two parallel hulls held together by a single deck that provides an extensive storage area. Lorries are shipped on the Danube by means of two different types of catamarans; one of them is built in Germany, the other one in Serbia. Both types are different in terms of design, number of crew members aboard and, to some extent, of moulded depth. According to their design, German catamarans are so-called semi-catamarans, that is, only the bow is double-hulled. They have an overall length of 114 m long, a beam of 22.8 m, a moulded depth of 3.0 m and a maximum draught of 1,65 m. Their crew comprises 12 members.
Serbian catamarans are actual catamarans, that is, the hull is entirely divided in two parts. They have an overall length of 114 m, a beam of 22.8 m, a moulded depth of 3.3 m and a maximum draught of 1.65 m. Their crew comprises 16 members. These catamarans provide a deck area of 2,500 m2 for lorries and can house 49 vehicles.
The international shipping agency Willi Betz GmbH & Co KG has taken over four catamarans of the state-owned Bulgarian shipping company SOMAT and has created a roll-on/roll-off regular scheduled service on the Danube. Two of the vessels are catamarans, the other two are semi-catamarans.