[The_Reader_David]

Okay, but can they tilt the kite so that the lift from the wind blowing obliquely to the direction of travel helps pull the ship? If so, then there would be
an analog of tacking.

Hmm, someone suggested helium: if one filled some of the chambers with helium and others with air, one could get the kite to tilt, making a sideways airfoil like a mainsail. Is there a way to do that within the parameters given in the article?

[USFRIENDINVICTORIA]

"... get the kite to tilt, making a sideways airfoil like a mainsail. Is there a way to do that within the parameters given in the article?"

The article didn't provide too many other details about the technology. Your idea seems reasonable to me.

Kite-boards can literally run circles around sailboards. They can also jump over them if they have to -- but, I don't foresee freighters getting much air. :-)