Roll-on/roll-off

Ro-Ro ships ( of English Roll on Roll off ) are ships carrying goods moving in RoRo method. This means that, contrary to LoLo procedure, that the cargo is driven on the ship. These are usually a combination of vehicles such as cars or trucks or trains that can travel on board the ships themselves, as well as standardized loading units and swap bodies that are dammed by special tractors on board. RoRo vessels have purposely equipped with decks on which the vehicles are driven. These are often variable in height, so the cargo space can be used more flexibly. For loading and unloading RoRo vessels have front, side or rear hatches through which the vehicles can drive over ramps on board.

Advantages of the RoRo method are in short turnaround times, gentle handling of cargo, port infrastructure easier and flexibility in the charge composition. Disadvantages are the higher construction costs, as Ro-Ro vessels are specialized ships and are often built to specific requirements out. In addition, the use of cargo space is not optimally solved. Within the short -sea shipping and for some special charges ( automotive, paper), however, outweigh the benefits of RoRo systems.

History

The principle of the Ro-Ro vessel was already known during the Crusades. It took time special ships for transporting horses and built for this purpose, so-called " Torschiffe ". 1123 the Venetians transported horses for the first time over a long distance with numerous stops. 1129 Hugo embarked from Payns in Marseille with many horses, horsemen and foot soldiers a. During the Byzantine- Roman expedition against the harbor town of Damietta in Egypt in 1169, the Byzantines had their ships modified so that the horses could be brought on board and on land via a ramp.

Joinville described this " Torschiffe " fifty years later as:

As the inventor of the modern railway ferry to Thomas Bouch.

Today's meaning

Today, the transportation of goods by ro-ro vessels in the short and medium-haul maritime transport is a significant size. The majority of truck traffic between Finland and Western Europe (including ports in Lübeck, Rostock and Kiel) is handled by means of RoRo ships. However, there are transatlantic and global ro-ro services, mostly auto transporters or in combined transport with containers.

Special types of RoRo cargo ship are:

  • Car Transporter
  • ConRo ship ( combination of container and Ro-Ro )
  • Ferries, with or without the possibility of passenger transport
  • Landing ships
  • Military transport

Security

Need RoRo vessels to accommodate the load, large openings in the outer skin. This can pose a risk, as in the case of faults or incorrect operation could penetrate large amounts of water through these openings. In conjunction with the large, poorly dividing cargo spaces and most mobile charge, this can lead to a rapid, critical stability change, which could result in a serious accident. For this reason, SOLAS writes more than once redundant backup systems, frequent exercises and technical inspections.

The greatest risk for Ro-Ro ships are the large free surfaces of the holds dar. Permeating water can be distributed almost unrestrained in the vehicle deck. If this water is not given continuously over scuppers or bilge wells by powerful outboard, the increasing weight can lead to a strong heel up to the capsizing. Despite everything there was in the past, some disasters on RoRo ships:

  • When the ferry Herald of Free Enterprise, the water penetrated by a not yet closed bow door, which meant that they capsized within 90 seconds after leaving the harbor. The International Maritime Organization responded after the sinking and pretended precise arrangements for the outer skin doors and safety equipment on ro-ro ships.
  • At the downfall of the Al -Salam Boccaccio 98 apparently resulted in the vehicle deck collecting firefighting water for heeling torque.

With such a large heeling skin sites may also come under water, that are not waterproof constructed ( eg exhaust valves, supply hatches, etc.). The consequences are secondary floods, nachströmt by the even more water and the ship finally capsizes and sinks.

Sunken Ro-Ro ships

  • Princess Victoria 1953
  • Salem Express 1991
  • Heweliusz January 1993
  • Estonia 1994
  • Al -Salam Boccaccio 98 2006

Capsized and again salvaged Ro-Ro ships

  • Sloman Ranger June 12, 1981 ( in the Mediterranean capsized after collision, again salvaged )
  • Herald of Free Enterprise 1987 ( capsized in Zeebrugge at port exit, later in Kaohsiung ( Taiwan) scrapped )
MS Herald of Free Enterprise MV Princess Victoria MV Salem Express MS Jan Heweliusz MS Estonia
691505
de