GL Container Forum: How Big will the New Container Ships Get?

Hamburg, 4 March 2005 – Just how big will the container ships of the next generation get? What structural challenges must be surmounted to meet the constraints of operating economy? Where are the production-specific limits in the manufacture of propellers and engines for even larger container ships? And what expectations do the port terminals have of the transport system “Ship”? These questions formed the thematic focus of the 6th Container Forum at Germanischer Lloyd, in which more than 70 customers and business partners took part. The current and future parameters for large container ships were outlined by Lutz Müller, Director of Ship Technology at Germanischer Lloyd. At present, Germanischer Lloyd is working on the calculations of design studies for a 12 770 TEU vessel. Here the IMO “fuel tank location” regulations expected to come into force from August 2007 have already been anticipated. With regard to the torsional stiffness of the hull, Mr. Müller referred to the risks of the new welding procedures which lead to a partial reduction in strength. Moreover, he explained that the cargo arrangement on board was limited by the structural strength of an ISO container. More than 10 container layers below deck were not feasible. The loading on deck – almost 60 percent of all containers being stacked on deck – was posing new challenges for the cargo securing systems. Lashing bridges for 4 or 5 layers, or open-top designs, were necessary to ensure safe stowage also for heavy seas. The optimum size of a propeller for very large container ships depended on the propulsion output and the speed, said Christian Johannsen of the Hamburg Ship Model Basin (HSVA). He referred to diverse options which were available for improving the efficiency of a propeller. Even cavitation damage could be minimized by ”propeller tuning”. With model trials under realistic conditions, as offered by HSVA, valuable information could be obtained on the turbulent flow. With regard to larger and considerably heavier propellers, Manfred Urban, Managing Partner of Mecklenburger Metallguss, drew attention to the installation problems. Particularly in the event of propeller damage, many repair yards were no longer able to mount today’s large propellers, which have weights ranging up to 140 tonnes. Dr. Peter Sunn Pedersen, Executive Board Member at MAN B&W Diesel, spoke about ”two-stroke engines with an output of over 70 MW“. For the propulsion of larger container ships, MAN B&W was offering a series of 12- and 14-cylinder engines of diverse types. The power range for an output with approx. 100 MW included six engine versions, about half each for single- and twin-propeller types. Engines of the latest design were much more compact, lighter and at the same time offer more power. In detail, the speaker described the dimensioning of the engines, the performance parameters and the thermodynamic challenges. The introduction of electronically controlled engines had led to an appreciable increase in output together with improved operation, e.g. at very low sailing speeds combined with low rpm. The questions on the requirements for large container ships from the viewpoint of a terminal operator were answered by Captain Heinrich Goller, Managing Director of the Container Terminal Altenwerder (CTA) in Hamburg. He emphasized the necessity, when constructing very large container ships, of taking due account of the limits imposed by the water depths. Ports were more easily able to adjust for broader ships. With a large number of examples, proposals were given on how the loading and unloading could be organized to exclude time delays. Since quay footage was a scarce commodity, it was important that ships arrived punctually and did not list during processing, so as not to hinder the loading and unloading work. The removal of the cargo securing systems for deck containers took up to 15 percent of the entire processing time. For this reason, reliable automation systems were needed. Although open-top vessels with cell guides caused greater lifting heights, the high hoisting speeds of modern container bridges meant that this was not a problem in comparison with lashed cargo. Furthermore, processing could be speeded up considerably through auto-identification of the container.

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