Following on industry feedback since the new container securing arrangement rules, Lloyd’s Register (LR ) has now created the BoxMax notation. BoxMax enables operators to load more cargo more flexibly, taking into account voyage (V) and weather (W) specific conditions, increasing efficiency and reducing operational costs.
BoxMax enables container ship operators to increase and optimise container stack weights. This approach has now been further improved by voyage and weather dependent criteria being incorporated into the modelling. The result is that the right stow and lashing requirements can be planned for any voyage at any time of year.
BoxMax builds on the same principles behind summer and winter load lines and freeboard requirements.
Stowage Planning Flexibility
‘No investment is required,’ comments Luis Benito, Global Marine Marketing Manager, Lloyd’s Register. ‘BoxMax is a smart solution to the needs of operators. Significant improvements in container stack weights can now be identified. Forces in a stack vary widely and vary between stacks at different locations in a ship.’ The new LR rules are meant to provide stowage planning flexibility to achieve the most cost effective container transportation.
LR was the first society to address the interaction between the complex, multi-degree of freedom motions experienced by a container ship and the consequential load paths through container stacks and their support arrangements.
Container Load Tests
Real containers have been load tested at full scale and ships have been instrumented; new insight for the larger 16-18,000 teu designs now emerging and for next generation 22,000+ teu ship designs.
Key Ship Motion Parameters
The BoxMax method uses ship specific factors, which define the key ship motion parameters of heave acceleration, roll and pitch angles and whipping accelerations in specific sea areas and for the required season. All the other ship motion acceleration values are dependent on these four parameters.
Stack Weights Can Be Greater
David Tozer, Business Manager, Container Ships, Lloyd’s Register, said: ‘Consider a container ship trading with “unrestricted service”, all year round, between Asia and Europe. For this trade the maximum container stack weight is one hundred per cent, that is the voyage dependent feature is of no benefit for stacks which are travelling the full distance. However, for stacks which are only travelling in the SE China or Mediterranean Sea areas for example, the stack weights can be greater. The assignment of the BoxMax (V) notation will denote the ship has access to this capability.’
‘Similarly, if the containers being shipped within these areas are being carried during the summer months, the stack weights can be increased, in some cases by up to 25 per cent. The BoxMax (W) notation will demonstrate this capability,’ he added.
For container stacks which are travelling the entire Asia-Europe voyage, the benefits of summer sailing may be relatively small, of the order two per cent, as Biscay may be challenging even during the summer months.
