Imagine sifting through thousands of stacked containers on a cargo ship to find a specific one meant for unloading? The worst nightmare is yet to come if the container happens to be somewhere at the bottom of the stack!
As you can see, haphazard stacking and stowage of containers on board a ship lead to the breakdown of cargo operations causing many serious problems.
These can include stack collapses and accidents, delays in offloading containers, delays in the departure of the vessel, etc....
https://www.marineinsight.com/maritime-law/understanding-block-stowage-in-shipping/