your boats crew's skill is deciding upon diving times etc. so with a diving time of 4 minutes to P depth i guess your crew is sleeping and you are doing everything by your self?
try the following:
- give
general quarters before diving (this puts all the crew in charge, and therefore speeds up the boats "skills")
- dont press "D" for dive, but
"C" for
Crashdive
cheers
morph
P.S. i was very delighted of the IX/D2 and i think to remember a diving time of 30 seconds ...