Stability of the container stack is a much bigger issue than the pure weight of the containers. On board a container ship, everything must be lashed down tightly anyways.
Also, sails apply lift, so upwards pull. I know nothing about sail physics, but this claim is in the OP.
Since port stays are very costly, you won't deploy this for anything shorter than a transatlantic voyage anyways. So the double-wide setup seems less of an issue.
Also, sails apply lift, so upwards pull. I know nothing about sail physics, but this claim is in the OP.
Since port stays are very costly, you won't deploy this for anything shorter than a transatlantic voyage anyways. So the double-wide setup seems less of an issue.