Container Ship Stacking Weight Modification Allows More Cargo

Advanced research and development by Lloyd's Register indicates that container stacking weights can be modified to allow the carriage of more cargo.

In an 18,000 teu design the increase in cargo weight could be as much as 10%, says Tom Boardley Lloyd’s Register’s Marine Director. The benefits are lower costs, lower emissions and a lower carbon footprint.

Commentary from Tom Boardley: "The results come from looking hard at ship efficiency – how can we optimise designs? Clearly there has been scepticism over many ship efficiency claims and much of the problem comes down to lack of common approaches to measurement, so you end up comparing apples with oranges. But the work that we have been doing in examining the forces involved in container stacks is throwing up some really interesting and innovative results.

These results indicate clearly that we will be able to allow much higher cargo weights and enable more operational flexibility – and to do this in safety. The potential in cargo increase is considerable. 
I must emphasise the safety element here. We are helping the owners reduce risks and further reduce uncertainties in container stowage planning and operations. We have been carrying out a broad range of investigation and re-formulation of calculations into operational ship accelerations and ship motions. This is not just mathematics – real containers have been load tested at full scale and ships have been instrumented; we have been modelling the impact of our new insights for the larger 16-18,000 teu designs now emerging and, looking to possibilities in future, for next generation 22,000 + teu ships.

The results have been really interesting and positive. In some locations, in some designs, you may have to reduce container weights. But having satisfied ourselves the risks are managed there are big benefits in overall carrying capacity. It’s not about more container slots – it’s about being able to load more containers that are carrying cargo and being able to have more options as to where to load which can help speed up cargo operations, reducing time in port, energy used and driving increasing asset efficiency ashore and afloat. 
The larger the ship, the bigger the benefit as the efficiencies are scaleable. The next steps towards final confirmation and the ability to offer new rules will go for validation by the Lloyd’s Register Technical Committee in November.

We have some really smart people who are working on this project and others like it that can help shipowners make some smart decisions. These latest findings are important and support the approach that we can make considerable savings through innovative research and a greater understanding of operational requirements and realities. Anyone looking at big container ships will benefit from this work.
There is still more work to be done. But we will be changing our rules and hope to bring this into practice soon."