Stowage planning and Yang Ming’s ‘Mobility’ explosion in Ningbo (9 Aug ’24)

Stowage planning of a large containership is an art and a science, claiming the brightest of our students and the use  of the most advanced algorithms of operations research.

This may sound surprising unless one things that the stowage exercise involves something like five loading ports in Asia and an equal number of unloading (and loading) ports in Europe; the need to minimize rehandles taking the full rotation into account; considering ship bay allocations by alliance members; proper positioning of dangerous, reefer and oversized containers; loading the ship evenly in view of the small clearance between a large ship’s keel and the seabed at berth; to the extent possible, reducing the metacenter of the ship by stowing heavy containers as low as possible.

All this is done not only by taking the full rotation into account, but also the plans of the yard planners. These have similar problems to solve, trying to minimize both rehandles (a nightmare in ports like Hong Kong where one must store containers 7-high), as well as the movement of terminal equipment (cranes; chassis; straddle carriers; reach stackers; AGVs, etc.). Recently, minimization of equipment movements has one more objective to fulfill: environmental emissions.

Finally, the equation may need to include gate operations, regarding the arrival of export containers. Here, external tracks should interfere as little as possible with the movements of terminal equipment which, btw, should be available and ready to serve them: a synchronization issue. Thus, external tracks should wait as little as possible and be given priority if they must pick up an import container on their way out (known as ‘dual transaction’).

No matter how difficult, we often attempt the joint optimization of such problems, i.e. ship-terminal-gate. One can easily understand the complexity of the exercise, particularly if one considers that carrier and terminal operator do not always see eye to eye. HH