Credit: Flensburg University
In this movie of the flettner rotor ship UNI-CAT build by Flensburg University which is driven by a singel flettner rotor power bay a Solar pannel charged batteri pack, one can see just how powerful the flettner rotor vessel technology is in comparison to the normal sail technology seen on the sailing vessel in the background.
Lift coefficient from the sailing rig compared to the flettner rotor is a factor of 1 to 13, including the unique power control difference between the 2 sailing systems where as the sail system has to be reefed taking away the possibility of maximising power according to rapidly changing wind conditions, where as the flettner rotor just has to regulate its rpm according to the corresponding wind speed leading to the much higher utilisation of the different wind conditions.
The above also has a big impact on the general vessel safty, as there is no need for the crew to be on deck in adverse weather conditions, avoiding the many dangers and injuries related to the reefing of sails in these types of conditions.
The same can be said for the number of crew, where one on a normal sailing vessel like in background need 2 or 3 people to operate the vessel safely and efficiently, the fletter rotor ship only needs one person to the same job
Another key feature of a fletter rotor vessel compared to a normal sail rigged vessel, the the much higher wind angel, where the sail can only go as high as 40° degrees where the flettner rotor can go as high as 25% into the wind, leading to a shorter voyage time.