Kapitain, are you SURE the ADCAP can't dive that deep?
According to the information that we used for our mod, the MK48 can dive to 850m and the MK48 ADCAP can dive to over 1000m.
I'm pretty sure just about any nick in the hull at those depths would crush even the Typhoon. I mean, if you are 75% crush depth and you lose even a bit of structural integrity, the various laws of physics and their associated curves are way against you.
Of course, the Typhoon is only rated to 400m or so anyway.