Agreed. It is the point I have been trying to make. My belief is that when you take into account the weight of the material itself it is questionable whether steel is a good choice of material.
Given that it is a high maintenance material I don't quite see the point.
As for hitting shipping containers how many steel boats return to port each year with harrowing tales of encounters with containers ? Precious few I'd guess. Its a beat up methinks.
“Give a man a fire and he's warm for a day, but set fire to him and he's warm for the rest of his life.” Terry Pratchett