Yep, the Dive Rate mod breaks the Deep Dive function of TM.
Deep Dive is actually going to Snorkel Depth in the game, but the depth was reset to a value just beyond on what your sub can tolerate. Believe it or not, I checked yesterday and the stock game had no way to intentionally endanger your boat without having flooding damage. Amazing a subsim where cannot go to deep! Like a driving sim where you can go off the track! What were they thinking?
The real question is does anyone know if you go deep, if the AI able to detect and attack at such depths? Or is Deep Diving effectively a guaranteed escape route? Is this perhaps why RFB has not deep dive key?
Thanks.