Feature 4 | CARGO HANDLING AND DECK EQUIPMENT
From a ship’s productivity perspective,
we believe that it is important to be able to design a cargo handling system which is fully aligned with the ship’s hull design. In practice this means that the vessel’s hull properties must not set restrictions on the loading and operating of the intended container stacks, and while operating with the intended container stacks, the ballast could be adjusted to its minimum.
Why are some ships not optimised for their cargo? With the current way of conducting ship concept design, it is oſten not possible to obtain the best possible results. Tis is because the ship’s hull and its cargo handling system are treated as separate blocks, and not optimised as one entity. Furthermore, parts of the cargo handling system such as hatch covers, lashing bridges, fixed container fittings and loose container lashings are oſten not considered from an overall cargo handling system point of view, but also as separate products. This leads to the sub-optimisation
of separate parts of the system, and subsequently to an underachievement from a cargo handling system productivity perspective. Tis is the reason why many container ships with a high nominal capacity (over 6,000TEU) are operated with reduced utilisation rates. The cargo profile should, in part,
dictate the basic parameters of the ship’s hull design. However, it plays its most important role in the definition of the basic solutions for the cargo handling system, such as the arrangements for lashings, hatch covers and cargo holds. In itself, this system should be of minimum weight and therefore optimised in terms of cost and material use. It should be noted that by optimising the weight of the cargo system, the ‘saved’ weight can be used for the benefit of payload. Te effect is marginal, but it exists.
What if the cargo profile changes? We also need to consider that optimising a system for one cargo profile can have its drawbacks when it comes to cargo handling system flexibility, which in turn could lower productivity and therefore
114 The Naval Architect September 2012
increase emissions per TEU if and when the cargo profile significantly changes. Change is inevitable and can happen if a vessel is re-located to operate on another route or when the charter period ends and a new charterer takes up the operation. Therefore, while designing the ship, both the current cargo profile and future flexibility to accommodate possible cargo profile changes must be taken into account. One of our main goals with Safety at Sea is to also find ways of improving the cargo handling system concept throughout the ship’s lifetime.
Built-in environmental efficiency It is clear that the future will bring ever stricter measures to protect the environment, which the shipping and shipbuilding industries will have to comply
with. However, ‘green’ solutions are not just ways of conforming to legislation, or improving a company’s image, they make economic sense – especially in today’s turbulent economy and shipping business. The shipbuilding process needs to be
made more effective and it must serve its final purpose of optimising the cargo capacity for each vessel. To do this, the decision making process during the planning stage of a cargo ship needs to be re-organised. With our work with Safety at Sea, we are ready to help customers make the best decisions at the investment phase, and can provide cargo handling systems that improve the efficiency and environmental- friendliness of their investments. As a built-in feature, MacGregor cargo
handling systems optimise use of space, which improves the ship’s earning ability while promoting environmental efficiency. NA
Can changing the design of the ship to fit the needs of the cargo bring better efficiency for vessels?
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