Peter Gaertner studied mathematics and physics at Univ. Stuttgart, Germany, and after some years of research in physics he now works in an RD department in the automotive sector, developing oxygen sensors. With the age of 12, he started snorkling around naples, italy and fell in love with diving. Nowadays his first interest is cavediving, especially survey and photography in caves. The PSCR Rebreather is the tool he needs for long dives to accomplish the time consuming tasks. Because of his interest for the functional principle of his Rebreather he wrote software and models to predict the behaviour of the PSCR in real-world diving. Out of his experienced he gathered as project coordinator for the team “Cavebase” and as a summary of his talks and workshop he developed a program for a strongly DIR-minded PSCR-class which he now teaches as an instructor for PATD.