There are some in actual use though, for example this rotor ship that has docked at the Port of Vancouver: https://www.nsnews.com/local-news/what-is-this-strang

There are some in actual use though, for example this rotor ship that has docked at the Port of Vancouver: https://www.nsnews.com/local-news/what-is-this-strange-ship-in-the-vancouver-harbour-10769444 https://www.nsnews.com/local-news/what-is-this-strange-ship-...