That's all good and well, now call me stubborn if you like, but the link and that thread never adress anywhere
German hydrophones ! The link I posted is specifically about the GHG and a bit about the Balkon Gerat, and it clearly says that on the surface with the diesel engines running, the hydrophones do work of course, but they're useless. Imagine for a second, first the sound of the waves running against the hull and the exhaust and propeller noises, but also the sonarman with his poor headphone, trying to pick something between these noises while having 2 ~1500hp engines running at some 10 meters from him, crew movement around and so on. I'd like someone more savvy on uboats speaking on this, but I would bet the sonarman was simply not at his station while surfaced. I've never read anywhere "we were running 15 knots on the surface when the sonarman picked up propeller noises at 25km".
And that's my point (again), and since pictures speak louder than words :
That's with a GHG, and that's just plain silly. Boat stopped with a mirrorlike sea, ok, why not. But that ? Now whether it's in the "bug" or "enhancement" category is another thing, but don't tell me that's "as in real life".
Besides this reminded me of a genuine bug : on the screen, the contact is at 349°, it's impossible to pick up with a GHG since it has a dead angle between 340 and 020. That's because of a mistake in the equipment.upc file, when you choose a GHG, it actually installs a Balkon Gerat.