You think getting your sonar "destroyed" is bad then I have news for you...
You have yet to encounter the "watch crew suicide" bug in stock SH3.
I think it only applies to the IX series boats with a particular tower, but that's from a dim memory of the days when I first started playing the game, so it may affect other types with certain conning towers equipped. (Somebody clarify this, if you please.)
Here's what it is and how it happens...
If your conning tower takes enough damage that it is destroyed, the watch crew will be killed. This is how the suicide begins. The game's AI will automatically move more crew to replace the dead watch...and they in turn get killed by simply going up to the destroyed bridge. So the AI moves more crew to replace those dead crewmen...over and over until all your crew is dead.
There's only two ways to avoid this catastrophic bug. You can either avoid equipping your u-boat with the affected conning tower ( turm ), or you can install one of the super-mods, like GWX, NYGM, WAC, etc. Although, there may once have been a simple fix released as a mod for stock SH3 that you might still find for download.
Truth is that stock SH3, even patched to 1.4b, still has a great many bugs and plays more like an arcade game instead of a simulation.
It cannot be stressed enough just how
revolutionary GWX has been to SH3. I swear Ubisoft should hire the Grey Wolves to be part of the SH5 dev team! Once I tried GWX, I never went back to playing stock SH3.
If you have an older computer, GWX 1.03 and NYGM should run okay. I had very little trouble with GWX 1.03 running on a 2.4 Ghz Athlon with 256MB DDR266 RAM and an nVidia GeForce FX 5200 128MB video card. There were some stutters and lags, but mostly because my vid card was a real bottleneck. Using Lite Harbor Traffic and turning the video settings down a bit in the SH3 Options menu helped to keep the lags to a minimum, usually when there were large explosions or other huge particle effects.