dr hanke, this watch was originally made for the West German Navy under a military contract and hence as a tactical piece it should be ideally all black (which was perhaps why there was an all black version and the BUND version consisted of the black bezel). In light of this, it is conceivable why it did not adhere to the industry standards of diving watches. I do not know whether this watch was ever 'used' for tactical exercise but my guess to hazard one is that it probably did not make sense to wear a watch like that into either an exercise or a real confrontation. A digital one with a compass with tons of feature creep probably works much better.
given so, it is probably more interesting to see this particular watch as F.A. Porsche's baby (he wears a 2000) combining the best of the design sensibilities of the Hochschule fur Gestaltung Ulm of post-war Germany with the adventurousness of IWC daring venture into one of the best manufactured case ever.
now sjx, it is our collective benefit if you write another review on the 3511, which is a truly stunning watch! Great review.