With the increasing volume of consumables produced in the Far East, in China in particular, the regular lines operators ask for increasingly large ships. At the same time, one sees incident reports implying massive losses of containers and impressive fires that give good reasons to worry. Will the container ships continue to grow, and what are the main concerns industry must face? |
The advent of post-panamax accelerated growth rate. It is almost what occurred with the development of the VLCCs in the seventies, where it seemed that there was no limit with the increase in size. We know, however, that the “million tons” tanker never materialized and that the typical VLCC was stabilized with the actual 300.000 tons, which seems the most current size for the VLCC. Will the growth of the container ship continue or will the curve of growth stabilize? It is the cost per EVP per mile which is the leading force, and it is the economy of scale which will feed the growth, but the marginal profits will probably decrease with the increase in size. Thus according to the probabilities there is an optimal size that the largest ships will reach. In the same way, in the segments of the different sizes, there will be an optimization that will be carried out, just like with panamax. There are a few years largest panamax were of the 4000-4500 EVP. |
TECHNICAL RESTRICTIONS |
ILLUSTRATION OF THE RISK |
Fires in containers were the subject of many press articles these last years. Enormous fires involved the abandonment and the loss of large ships, such as HANJIN PENNSYLVANIA in December 2003. Fires are often associated with sensitive cargoes such as the calcium hypochlorite, an oxidising agent which can ignite spontaneously under certain conditions. Extinguishing such fires can be a real problem because oxygen is released by the burning product, which contributes to feed the fire. A current fighting method against these fires consists in isolating the pile of containers on fire by drowning it with water to prevent fire extension, and letting the pile burn until the end. The damage is generally considerable, such as the case of CMA DJAKARTA. The ship had a hold completely destroyed by fire, and had to be rebuilt at the same price as a new ship. The integrity of the hull is normally not a problem for container ships. We record only one accident concerning a container ship which broke in two parts, namely MSC CARLA. The container ships were always built with double side plating, double bottom and watertight bulkheads. |
Plating fatigue is a damage which was submitted to industry these last years. Serious cracks were discovered by German ship-owners on panamax type after only a few years in service. This problem is well-known on large tankers and bulk carriers but had not been, until now, observed at large scale on container ships. Although the technical cause of the cracks is different from that of the tankers, the remedy is almost the same. With the increased use of high-strength steels, the problems of fatigue must be studied carefully, because for the everyday use either the steel is ordinary or high-strength the lifespan is the same facing fatigue. So when the level of the efforts is increased when high-strength steel is used, it is necessary to pay special attention to the details of structure and concentration factors of the efforts to maintain the same lifespan in front of fatigue. Problems must be solved by design. For ships already built and in service, it is necessary retrospectively to calculate fatigue, an inspection program must be established paying attention to the detail before getting to the stress limit. That will make it possible to prepare budgets and plans and to carry out repairs in a controlled way. The alternative can be the occurrence of hull cracks which, if it happen on a fuel capacity, can cause an awkward pollution in port, involving an immediate suspension of charter party and repair expenses. Such unexpected incidents will certainly have a cost higher than planned and well prepared repairs. |
CONCLUSION |