Having re-read the article more I can see now that the sound detection
does in fact mean the sounds emitted by the screws running at high speed,typically on calm seas,where the noise would be harder to mask,more so at extremely close range.Therefore a drop in speed would be needed.
Having said that,firing at minimum ranges when allied detection methods was constantly improving would be nothing short of suicidal,forcing the UBoats to attack at ever increasing ranges.Especially so against large well defended convoys.
Interesting about the smell of diesel,again,a sure give away.Not much of a problem in SHIII though,unless there is even a mod for that!
