Report KD 485 describes five safety systems for which the rotor is turned out of the wind. For all systems it is assumed that the rotor has a certain eccentricity e. In stead of an eccentrically placed rotor, one may also use an auxiliary vane. This use is explained in chapter 4 of KD 584 for a flat vane blade with an aspect ratio of 2 : 1. The use of a new vane type which is made out of a vertical cylinder is added to chapter 4. A vertical cylinder has almost the same characteristics as an eccentrically placed rotor and is therefore a better alternative than a flat vane blade.