Depth keeping below 180m

[volodya61]

stoianm pitch&roll for SH5 - http://www.subsim.com/radioroom/showthread.php?t=183306

TDW Depth keeping problem - http://www.subsim.com/radioroom/showthread.php?t=179746

[Hoster]

Thanks,
but I`m already using the mod you mentioned. They keep the depth up to 170m, but not below.

[TheBeast]

Originally Posted by Hoster

Thanks,
but I`m already using the mod you mentioned. They keep the depth up to 170m, but not below.

Only reason for this that I can think of...

Below 170m, leaks begin to overwhelm pumps. If boat does not maintain enough speed, it will begin to sink. The deeper you go, the faster it seems to sink or slip away.

Does this sound logical?

[Hoster]

It seems, that nobody else but me is facing that problem mentioned above. Well the sub is in perfect condition with no leakings at all, but I can only hold depth below 180m at 3 or more knots. I thought it is a bug concerning everybody...

[Trevally.]

Originally Posted by Hoster

It seems, that nobody else but me is facing that problem mentioned above. Well the sub is in perfect condition with no leakings at all, but I can only hold depth below 180m at 3 or more knots. I thought it is a bug concerning everybody...

See this thread - It may help you http://www.subsim.com/radioroom/showthread.php?t=179746

Download here http://www.gamefront.com/files/21093845

[0rpheus]

Originally Posted by Trevally.

See this thread - It may help you http://www.subsim.com/radioroom/showthread.php?t=179746

Download here http://www.gamefront.com/files/21093845

Trev - he's using that already. His problem is depth keeping at low speed below 170/180m. I assume you're thinking of this post: http://www.subsim.com/radioroom/show...7&postcount=93

However - even with TDWs mod, you have to do 2-4 kts to maintain depth below 170, and that's too fast for IRAI - they hear anything above about 1 kt, so going deeper than 170 (risking crush) to avoid cans ends up being counter-productive: you make more noise than if you'd stayed at 160 or so, and they hunt you down all the harder.

I've never been able to figure out how historically accurate this effect is. I understand that buoyancy should drop below a certain depth (I think), but I also assume subs would have gone lower than 170 in some circumstances (and survived). Any history buffs have anything to weigh in?

I think in SH4 I can hold depth well below test depth at 1kt - whether that's realistic or not, I couldn't say. At the moment in 5 (with IRAI), there's no point - stay above 160/70 and be quieter, or go below that and be a lot louder. You can't win

[Hoster]

Thanks Orpheus, you got me absolutely right! Well I read, that the VIIc/41 could dive to 260m! Very often subs were forced down to 200m and much more (with silent running).
I´m using a lot of mods including Open horizon, IRAI, the U-boat historical modification mod....

[Hinrich Schwab]

Originally Posted by 0rpheus

I've never been able to figure out how historically accurate this effect is. I understand that buoyancy should drop below a certain depth (I think), but I also assume subs would have gone lower than 170 in some circumstances (and survived). Any history buffs have anything to weigh in?

From what I know, the boat would have to manually adjust trim to compensate both weight and air compression due to Boyle's Law. When coming back up, the trim and air pressure levels would have to be vented to avoid rupturing the tanks as the air pressure increases as depth decreases. Even then, I would hazard a guess and think that at least 2-3kts would still be needed. However, the issue is possible cavitation and sound propagation at that depth. Active sonar, especially late war should still have little issues with a boat at ~180-200m. However, water pressure should allow a boat to operate at faster speeds without passive sonar picking the boat up. I know the Sonalysts sims model this, but I do not think any of the SH games do. Add thermoclines to the mix and there are all kinds of fun variables that should be in play, but the sims either do not deal with or oversimplify to a degree that either gives too much favor to either the sub or the destroyer, depending on game and instance.

I know that this copy of the Type VIIC manual has all kinds of fun performance data with sound propagation and detection.

http://www.uboatarchive.net/Manual.htm