[mmooss]

> How much sail area would it take to move a 20000 TEU ship at, let's say, even 12 kts? How tall would the masts have to be? Would they fit under bridges?

For ocean-going ships, isn't 99.x% of the trip in the open ocean? If so, what limit is there on sail dimensions? It's a genuine question; if coastal infrastructure isn't the limit, what is the next limitation.

They could lower sails, and use a motor and/or smaller sails, around coastal infrastructure.