The expansion of offshore wind power in Germany is steadily progressing. With the addition of 108 offshore wind turbines (OWTs) in the first half of 2017, a total output of approximately 5 GW was achieved. This corresponds to a total of 1,055

OWTs connected to the power grid (Lüers et al. 2017). The increasing use of offshore wind energy (OWE) leads to the need to maintain the increasing number of OWTs during their operating phase. The most important aim of these maintenance efforts is a high availability of OWT. This is impeded by limited reachability and high logistics costs due to the rough conditions at sea (Oelker et al. 2016, Burkhardt 2013). To solve this dilemma, maintenance strategies have to be optimized (German Federal Ministry Economic Affairs and Energy 2015). Particular challenges in the maintenance of OWTs in comparison to the maintenance of onshore wind power plants result from the weather-limited accessibility as well as from the coastal remote location of offshore wind farms (OWFs) with the related costs for personnel or material transport via special vessels or helicopters (Oelker et al. 2016).