- November 15, 2021
- Posted by: svm
- Category: Uncategorized
Contributions by Kishore Balireddy, Mohit Oberoi, Miguel Angel Saez Perez and Jes Tousgaard
For years, the process of transporting goods worldwide has been a tedious and expensive one. It was only until containerization that this became easier for both companies and consumers alike with an estimated 793 million TEUs handled in 2019 through over six thousand active ships globally.
Container shipping is one of the fastest, cleaner and easiest ways to transport containers. The size and technology in our industry has made it possible for container ships to carry more than 20,000 containers at a time with around 8-10 stacks lashed together, making long series on board each ship. However, lashing planning is one of the most important, and potentially dangerous roles, as it involves the optimized securing of containers to the vessel. When it goes wrong, it can not only cause containers to be lost overboard, but it disrupts supply chains and customer relations, and can cause terrible harm to people and to the environment.
The Importance of Optimized Container Lashings
When a container is loaded onto a container vessel, it is fastened to the ship’s structure and to the container stacked below by means of lashing rods (pictured right), turnbuckles, twist-locks etc.
This is to prevent the containers from shifting, collapsing, or breaking free to be lost at sea during rough weather or heavy winds.
Lashings are there to mitigate the effects of wind, as well as six forms of motions acting on the ship when the vessel is at sea. Rolling and pitching are a part of every ship that is going out to sea, however “parametric rolling” – where the ship starts to roll in head or stern areas – is a type of movement that is unique to container ships.
This is due to the increased size of container vessels, and that newer container ships have a larger bow flare (pictured right) and wide beam to lower frictional resistance. This creates heavy stresses on the ship’s structure, and can result in lashing systems failing, with containers thrown overboard.
Ideally, the person who plans the container lashing should be competent enough to understand the variables in play to avoid such a catastrophe.
Lashing forces play an active role in maximizing the vessel’s cargo intake. Although Class Societies have created flexible lashing rules (route-based rules), exceeding lashing forces is still one of the main factors that play against lifting capacity.
The benefits of an optimized lashing plan include safer sea passage without container loss or container damage at sea or port, plus an improvement in fuel efficiency and vessel performance. However, probably the bigger benefits of such an optimized lashing plan, is the increase in loading potential and vessel productivity.
The Current State of Lashings Planning
Planning is the lifeline of the entire shipping operation.
Mohit Oberoi – Founder and Director of Solverminds Solutions.
Planning determines how many booked containers can be loaded on the vessel, which ultimately determines how profitable the ship will be for that route. To do so, planners need to quickly simulate loading and lashing to test if the ship can take this, and possibly more, containers.
A container vessel loading has to comply with established lashing rules. When lashing rules are not adhered to or weights incorrectly declared, it causes tremendous damage to the vessel. Add to that the fact that containers have various weights, and the planner has to stack each stack individually in order to remain compliant with lashing rules. This takes many hours. Imagine a large-sized ship, with 20,000 TEUs with 30 rows across and 11 high, with 100 bays, the complexity of creating such a compliant and efficient plan is enormous.
For this reason, lashings planning is a tedious, manual and error-prone activity that is high-risk and painstakingly slow. If there is a change in the container forecast, replanning the ship takes a long time.
Furthermore, planners do understand the planning aspect and are aware of their obligation to managing lashings, however, we have noted that the “thumb rule” approach is what is resorted to and which allows planners to plan containers, as opposed to checking lashing conditions every time a container is added, shifted or replaced.
The broad steps that a planner would thereby deploy would be:
- Plan the stacks in bays
- Check if there is any issue with the lashing forces
- Iterate and reduce the weights and fix the lashing parameters if outside limits
- Ensure wind forces are under control
While doing this, the planner usually plays it safe and refrains from pushing the limits of all forces – being racking forces, lifting forces, compression forces, lashing rod forces and stack weight forces – to near 100%.
Nobody has mathematically optimized lashing forces which would open the door to further explore opportunities that thumb rules may not expose.
That is, until now.
The First Automated Lashings Planner: Optimized Operational Efficiency in a Matter of Clicks
Solverminds has done it again! As their name implies, Solverminds – the international tech organization known and trusted in the maritime sector for their intuitive Liner ERP solution – has solved yet another shipping challenge with optimization and AI / machine learning (ML).
“Our stowage optimizer – SONATA – which automates stowage planning for maximized utilization, is now equipped to automatically plan and optimize lashings,” says Capt. Vijay Minocha, Chief Commercial Officer of Solverminds.
SONATA helps planners plan each ship according to the ship’s unique criteria and the bay’s specific load list.
“We modeled the lashing rules and built smart equations to automate lashing rules,” says Mohit. “Mathematically, this was an extremely challenging calculation that needed to be done, and the very best minds in the Solverminds team were put to the task of automating the plan.” These algorithms bring several years of manual planning experience by way of automation.
Not only does the optimizer take racking forces, corner post loads, lifting forces, vertical load, as well as metacentric height (GM), wind forces, partial exposure of containers, parametric rolling, uneven sizes and various weights, and various stack heights into account, it also produces a plan that is 100% compliant with lashing rules.
This is quite a feat, considering that each container has 20 dimensions on its own. Factoring that by 200 slots creates a huge matrix of combinatorial optimization.
Additionally, while manual planning might see the selection of heavy containers at the base of the stack, with ever-lighter containers stacked on top, the optimizer pushes the limits of the weightage and TEUs safely, thus increasing container capacity and maximizing profitability.
What used to take the planner a very long time to do, with tremendous effort, now – with a simple click of a button – a lashing simulation is generated that is constantly seeking to maximize stack height for an optimized TEU percentage.
No more tedious hours of manual calculations.
No more inflexible plans.
No more human errors and timid stacks.
Your lashing plan is agile, profitable, and optimized, with SONATA.