My small 12 meter long boat has a sail area of 900sqft. When sailing perpendicular to the wind it captures pretty much all of that.
The sail on that ship is 100' high, and looking at the aspect is around 15' wide, or 1500sqft. That type of sail I think only harneses half of that area, so half of 1500' or 750' best case.
I can say with complete confidence that if all the energy from two of my boats were towing one of those ships, even in a hurricane, it's going to increase fuel efficiency by approximately 0.0%
EDIT: I just did a random sample of wind speed [1] of points on the globe on international shipping routes [2] and it looks like they are generally around 10-15km/h. Thats barely enough to get my boat up to speed. There is a reason sailboats take very particular routes and don't just go from point A to B
The sail on that ship is 100' high, and looking at the aspect is around 15' wide, or 1500sqft. That type of sail I think only harneses half of that area, so half of 1500' or 750' best case.
I can say with complete confidence that if all the energy from two of my boats were towing one of those ships, even in a hurricane, it's going to increase fuel efficiency by approximately 0.0%
EDIT: I just did a random sample of wind speed [1] of points on the globe on international shipping routes [2] and it looks like they are generally around 10-15km/h. Thats barely enough to get my boat up to speed. There is a reason sailboats take very particular routes and don't just go from point A to B
[1] https://earthjustice.org/sites/default/files/world-cargo-shi...
[2] https://earth.nullschool.net/#current/wind/surface/level/ort...