Please note this ship was quite unique to begin with: it's a 5-year-old 12-deck cruiseferry that burns gas instead of oil. https://en.wikipedia.org/wiki/MS_Viki

Please note this ship was quite unique to begin with: it's a 5-year-old 12-deck cruiseferry that burns gas instead of oil. https://en.wikipedia.org/wiki/MS_Viking_Grace https://en.wikipedia.org/wiki/MS_Viking_Grace Here's an image of the ship with the new rotor sail on top: http://www.maritimeherald.com/2017/cruise-ferry-viking-grace-install-turbosail-for-hybrid-usage-of-wind-power/ http://www.maritimeherald.com/2017/cruise-ferry-viking-grace...