In the photo of a container ship cargo seems stacked 12 high. I do know that there's lateral supports etc. that are not visible in the figure, yet the vertical load, isn't that transferred downwards to the bottom container? Or is there some way to support the stack at an intermediate point so that the bottom container in a stack does not take the compressive load of the 11 units above it. At 30 tons a container, with 4 corner posts / twist locks that'd be 80 tons per bottom container's corner post. I do know there's ship mounted structural columns / cells / bulkheads above deck on these vessels but I thought they provided lateral stability. If you wanted to transfer vertical loads I cannot think how to do that without obstructing access to the cranes that lower these containers into the stack. So how do they manage the vertical loads? Or are these 12 high stacks composed of empties high in the stack?