Sixteen loss of position incidents on fourteen units are reported to us from the petroleum activity on the Norwegian continental shelf, from 2014 to 2018. The incidents had a mixture of severity, with pollution of 360m3 mud, damage to drilling and production equipment, falling objects and three autolifts of bridges as the most severe consequences. The incidents are described briefly and the most common causes of the events are found. The cases are discussed in view of several approaches. The barrier concept, and modifications of previous established barrier functions and barrier elements are discussed. I discuss the man-technology-organisation examinations in the investigations. Further the application of the single failure analysis philosophy is reviewed, and I discuss limitations to the method based on our cases. Our cases are compared with previous learning from incidents on shuttle tankers. A discussion is done on the slow reactions to changes in the weather conditions. In the last section I discuss needs for improvement.