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Big ships, big loads?

Big ships, big loads?
In the current era of bigger is better in container shipping, there are technical issues that many shipowners may not have considered when building their ships and this may adversely impact them in the long run.

According to MacGregor Cargo Handling Systems director for sales and marketing Tommi Keskilohko and Ari Viitanen, who is responsible for customer solutions, there can be a difference of up to 10% in terms of payload capacity between the nominal and actual capacity of the vessel.

“As containership sizes increase, one should pay special attention to the fact that in many cases the actual capacity does not follow suit. The nominal capacity may be big, but may not allow for example, carrying the full weight of container stacks required by the cargo profile, thus some of those containers need to be empty or there are many restrictions as to where containers can be positioned onboard a ship, or the arrangement may require additional container moves during loading and unloading,” they said.

“There are not enough people in the industry who can see this and who can define the actual maximum capacity together with the ship’s owner. We want to highlight that what matters is the transport capacity of payload containers, not the number of containers as such,” said Keskilohko.

Viitanen noted that even ships with the same hull design can differ in terms of actual payload capacity. “When designing a ship and its cargo system, the investment efficiency is the key. An optimised cargo system can bring back the additional investment in a few roundtrips so the capital expenditure is non-significant considering the ship’s overall earnings during its lifetime,” added Keskilohko.

Factors affecting the actual capacity, or causing failure to reach the best possible payload capacity include a sub-optimised hull and cargo system, sub-optimisation within the cargo system as each part may be optimised, but with no holistic view there could be weak links affecting the final result, wrong orders in the design process, and failure to commit to an integrated system delivery at an early stage of the project, but instead purchasing system parts piecemeal from various sources with decisions based on lowest price.

The processes, software and hardware all should develop at the same pace with the increase in ship size and these should be able to handle higher container stacks, for example, six-tier high compared with 10-tier high, MacGregor says.

For owners and operators, the first-in–last-out issues are set to increase because the container stacks are getting higher and the hatch covers are getting wider and this will in turn impact on the ship’s utilisation rate and revenues, said Viitanen.

Clearly, efforts should be spent on cutting down additional container moves because they have a direct impact on the operational cost. He suggested two ways of improving the process:

1) By making the information more exact, ensuring that it is reliable and comes at an earlier stage when preparing for loading/unloading.

2) Change the cargo systems so that they allow for more flexibility such as a bigger weight window, allowing more alternatives in the cargo planning at a later stage.

“The first option is challenging to achieve, while the second is easier to influence although they both complement each other so the first option should still be taken into consideration,” said Viitanen.

“As long as there is no standard of defining the actual capacity in an unambiguous way, there is no way to compare ships and to trade them according to their true performance. We assume that enabling such comparison would be important. For example within shipping alliances,” pointed out Keskilohko.

For example there is a disconnect between the standard performance indicator while sailing of cost per teu per nautical mile, and for in-port operations of cost per teu per container move, and how many moves or re-stows are needed during loading and unloading, he said.

As long as there are no clear standards defining actual capacity and their operational efficiency, ships are being bought and traded based on wrong criteria, said Keskilohko.

“MacGregor has done research in this field and our viewpoint is that all this can be influenced by a holistic and optimised cargo system design and processes, and by doing so the earnings of the ship owner and operator can be improved,” he added.

For example, Viitanen pointed out that the actual maximum capacity and the nominal payload capacity onboard the recently delivered UASC 15,000-teu mega-boxship Sajir is equal and having been in service since November 2014 the figures speak for themselves.

“Decisions on cargo system investment at an early stage of the project, as well as early decisions regarding chartering plans are prerequisites for an optimised cargo system,” concluded Keskilohko.