Not really metal working in the video, but products of metal working
in the form of stacked Conex boxes and the ship hull undergoing some
severe strain testing in rough seas.

http://www.liveleak.com/view?i=bb1_1320213221

In conditions like that, you'd better hope some of those boxes don't
let loose and unbalance the load.

I am not completely familiar with how these boxes lock together when
stacked on the ship.

Do they just stack them up like Legos, where the bottom box locks to
the deck and the next box locks to the top of the lower box and so
forth? So, the strength of the entire stack is dependent on the
strength of the lock down of the lowermost box?

If so, the strain on the lowermost box in seas like this must be
incredible.
Dave
Dave