Special tankers transport the following liquid goods:

• Mineral oil and its derivatives – petrol, diesel, heavy and light fuel oil, etc.
• Chemicals – acids, alkalis, benzene, styrene, methanol, etc.
• Liquid gases

Most of these goods are classified as dangerous material. To ship them, the tanker industry uses special vessels that meet the corresponding safety requirements. The European regulations and recommendations as described in ADN, ADN-R and ADN-D, as well as the national legislation on hazardous material are particularly relevant for this industry.

Modern vessels are double-hulled in order to prevent the dangerous cargo from leaking in the event of a rupture. The cargo hold is mostly divided in several individual tanks that can be separated into completely detached areas. This means that the lading and the extinguishing equipment, the residues and gas displacement pipes, as well as the residues tanks are thoroughly separated. These systems and equipment are necessary to prevent contact of toxic steam and liquids with the environment. In order to prevent chemical reactions between the surface of the tanks and these goods, tanks and cargo holds are covered with special coating. By heating the tanks and by means of valves, goods with a low freezing point can also be shipped in winter. On the other hand, sprinkler systems on deck protect the tanks from rises in pressure caused by solar heat. Shipping liquid goods demands state-of-the-art technology. To mention but an example, the “Ursula Valentin“ of the German shipping company Reederei Jägers GmbH transports goods as in a thermos flask at a constant temperature of 220° C.

Liquid gas is transported under pressure and refrigerated in special canisters. Nevertheless, this type of cargo is very rare on the Danube. Most tankers have pumps on board, so that loading and unloading liquid cargo is also possible at ports lacking special transhipment equipment. Tankers on the Danube in which no pump is yet available on board are being equipped with it. A vessel has mostly two pumps since, basically, each pump may be used only for one particular liquid good. The dimensions of the biggest inland tankers on the Rhine are 135 m x 11.45 m with a draught of up to 3 m and a deadweight of about 3,000 tonnes. The tankers that navigate the Danube have an average deadweight of about 2,000 tonnes. As happens with dry cargo carriers, tankers are used almost exclusively in pushed convoys or coupled formations.