I hate this "destroyed by pressure"
 

I have been depth charged for over an hour now by 4 DD's, and its really annoying.. Some times I can dive to 150m and sometimes I cannot even make it to 110m (I keep reloading, I don't play dead is dead)

its really annoying why this happens.. I understand my hull could of been damaged, but nothing is broke as of now.. And eventually if I pass a certain point (130m or so) I start to hear the stupid electrical noise and then BAM, instant death screen, with Destroyed by pressure..

Its really annoying..

I am also trying everything.. Cruising at 50rpms or even less, making my depth random, and no matter what, eventually within an hour (about 30 minutes game time, as you can tell why I am so annoyed) I DIE!!

I feel like surfacing and just taking my chances with my deck gun (LOL)

I am also turning (no more than 5 degrees rudder) every which way, and dropping decoys (are they even useful? If so whats the trick with them?)

Can someone give me some advice please? Thanks guys!

edit* BTW its 1942 and GWX3, in a VIIB and I just sunk a nice fat bogue class carrier and I don't want to reload before this.. :(

Do you know what your Hull Integrity % on crew/damage management screen is or is it hidden??
Even if you don't know for sure, I strongly suspect your pressure hull is damaged and it only gets repaired in port. Even if you are not showing any damaged components any more.
If that is true and you can't get past 130m , the chances of evading 4 DDs are slim (or closer to none).
If you still want to keep your carrier score then I'd recommend giving up on trying to go deep and try to evade the destroyers at 110m (or whatever your deepest safe depth is) like you said, 50rpm, turns and flank speed during the depth charge runs. Sorry to say I don't fancy your chances. Good Luck.

This goes against the grain of many here, but it's my method.

Set turns at 90 RPM. That is, a hair under 2 knots.
(This was the actual Silent Speed for Type IXs. Don't know about Type VIIs.)
Refrain from turning as much as possible. It interferes with evacuation of the vicinity.
In the case of your hull, I would consider 100m.
(If 130m is at/about your limit, your hull is already an eggshell at 100m.)

At 50 RPM (Dead Slow) you will travel 3 miles (about 6000m) in 3 hours.
(Not good).
At 90 RPM (Silent Speed) you will travel 6 miles (about 12000m) in three hours.
(Better).
At 50 RPM they always know where to find you. Right where they left you.

The decoys/bolds are good for iritating a DD. Releasing one bold increases your chance to stay undetected for the duration of the bubblescreen by 50%. But it attracts a second DD to investigate the area. If you release a second bold a third DD will show up and search for you and so on.

One lonely DD is distracted with one or two bolds and you'll have time to move away.

DDs of an convoy escort screen will call for help if you release a bold. May be useful after some time dealing with only one watchdog. The second DD will need some time to reach your position and you'll have better chances to get rid of No.1. Still close to the convoy maybe not the best option.

It'll be pretty hard to shake off 4 dogs that have your scent....just like it must have been in RL.

One method would be to save the game then reinstall the save, the DD's will more than likely lose their waypoints but you'll also run the risk of experiencing the 'dive of death' phenomena.

Ha! Ain't karma a beeyatch?!

For an undamaged VIIC what's the farthest depth I could dare go (and I mean the farthest)? With 100% integrity is the das boot scenario of going beyond the gauge even possible?

YEP!!!

I went to 300 and brought the TC to 128, and was fine, until about 30 seconds real time.. Then I died.. But was able to do it for a good 10 minutes (game time)

BTW can someone tell me what the random max depth deal is on commander? THANKS!!

Then you are dealing with a hunter/killer group and the destroyers are almost certainly at least veteran, possibly elite, and they are not happy with you at all.

Max depths are randomized because in real life there was no perfect maximum depth, and only one way to find out how deep that really was. Some boats came back claiming extreme dives. Others didn't come back, and we don't know why.

It's completely dependent on how, and if, your install is modded.
Most mods alter the max depth, to your benefit, but not all mods use the same figures.
Be very careful in trying to apply someone elses experiences to your sim.
(Consider it as the differences in workmanship on each boat.)

I use GWX with a few non related GWX mods and the lifeboat mod. Randomize crush depth remains unchecked along with the stock SH3 VIIC. I think if required I'll only go halfway across the red zone in an extreme emergency.

I can't go as deep as you.
I usualy keep my IX (A), B, or Cs at 100m. (33 seconds for DC)
If I come across a sharp ASW vessel/group, I'll let her slide to 120m. (40 seconds for DC)
If things get realy desperate 150m (50 seconds for DC).
165m (55 seconds for DC) is as far as I'll let the boat slide down before starting up again.

(Keep in mind that I usualy try to drive IXBs, which are the shallowest divers of the big boats.)

I've used an IXB for most of my time playing the game, and I regularly push 260-280 when the escorts won't give up. I've hit 310, but started taking hull damage after that. Even with a bit of hull damage I can manage a good 240m or so. A temperamental mistress, the IXB can be, your results may vary.

Your results can vary is right.
What mods are you running?
(Those numbers are not even close, for a stock install.)

GWX3, SH3C with randomized crush depth.