The interest is rising. Here's the story about Viking Grace, a passenger vessel with the Flettner rotor: https://www.maritime-executive.com/article/viking-line-

The interest is rising. Here's the story about Viking Grace, a passenger vessel with the Flettner rotor: https://www.maritime-executive.com/article/viking-line-installs-rotor-sail-on-cruise-ferry#gs.wWbA3Ho https://www.maritime-executive.com/article/viking-line-insta... Here's a passenger's video about it. It spins quite fast: https://www.youtube.com/watch?v=Ir8YSRhMsXA https://www.youtube.com/watch?v=Ir8YSRhMsXA