A merchant mariner said the ship he was piloting carrying cargo traveled only 9 knots or a little more than 10 mph. Why so slow?

About three years ago the shipping lines noticed that they could save a lot of money by going super-slow. So that's what they do now. Any cargo in a hurry is going by plane anyway.

This leads to the thought, why not save even more fuel with sailing ships? It hasn't been done on a container ship level yet. The ECO-freight folks seem to have built a smaller sailing freighter.

A Dutch company has a web site saying that they are working on it. I don't think it will turn out to be practical. There are other considerations beside speed alone.

Some that come to mind are crew, safety, size of ships, masts, and sails. Modern ships are huge! I don't know that sails and masts big enough are practical.

Storms become much more of a factor with sailing ships. How would they get a giant sail freighter through the Panama Canal? Sailing ship crews need to be large and the sailors highly skilled.

I don't know, it is an interesting thought. Lighter than air aircraft are getting a second look now too. It turns out solar is being tried too but doesn't look like it has enough power to matter much.

I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.