[Penelope_Grey]

If your hull integrity is still 100% the VIIB should be able to reach 200m safely without sustaining damage, though, once you go beyond 220m that is when things really will start to get rough, after 220m its anybody's guess when the hull starts to buckle under the strain.

In the early part of the war, the allies were not very good at anti-submarine operations because there were a number of factors like;

1) they were not entirely sure what the capabilities of the U-boats were, as in, they were not certain how deep the U-Boat's could actually go to escape.

2) Asdic limitations. Early war Asdic was not great. The range on it was not very good, at 160m you should not be hearing any pings anymore. But, they will still be able to get you on hydrophones, so your best course of action is to keep silent running and silent speed.

3) Inexperience, most of these crews had little to no experience in hunting down enemy subs. They literally were in many cases just dropping depth charges and hoping for the best.

These three things played right into the U-boat's hands and they were sure to exploit these key factors in the early goings.