Sub keeps sinking!?

[smg13]

Hello.

I am having a weird problem... when I dive, my boat keeps sinking past the ordered depth. Or sometimes it goes to that depth but then it is impossible tu surface.

I am currently using NYGM, and Realism Mod V16A3, and Stiebler addon to V16A3. I though it might have something to do with the silent running fix, but I deactivated it and still I sink. Any ideas or suggestions?

Thanks.

[Stiebler]

This is one of the features of the silent-running fix, as you guessed.

It is puzzling that it persists after you have deactivated the mod - probably you have not replaced the 'activated' mod with your new 'deactivated' mod. Or perhaps you have saved the game in mid-patrol with the SR mod active, and reloaded the game with the SR mod inactive, but the game remembers its old settings.

In any case, you can regain control simply by reverting in the game to 'noisy'-running. That is, tell the Chief Engineer to end the silent-running routine. You can always return to silent-running again afterwards.

Stiebler.

[smg13]

Thanks for the info Stiebler. I figured out two thing: First, it is NYGM mod that makes my sub sink once it is not moving. I have to move to keep depth. Is this the way it was in real life?

Second: Once I activate V16A3 and your add on for it, the specific problem I am having is, the sub not wanting to come back up beyond 20 meters or so. I am going to deactivate everything and star from a clean vanilla version up to your addon for V16A3 and try it out. Thtere must be something mixed up in my installation. I'll let you know how it works out

I love all your mods and I want to give you a big thank you for all your work. How is it possible a multimillion dollar game company can't do half of the quality work you and other modders do?

[Sailor Steve]

Originally Posted by smg13

Thanks for the info Stiebler. I figured out two thing: First, it is NYGM mod that makes my sub sink once it is not moving. I have to move to keep depth. Is this the way it was in real life?

All ships leak. That's a fact of life. Modern subs can 'hover', but they have computers to help run everything. Yes, sooner or later a WW2 sub would begin to sink if it was not moving. This could be controlled with the pumps, but they make as much noise as the propellors, which defeats the purpose of sitting still. This is why we have 'Silent Running'.

[smg13]

But I have a question... of course in "silent running mode" you turn off the pumps. But in "noisy running mode" you would have pumps running, correct? Even with engines stopped, there are many situations where you would want to hover with the pumps running, helping you keep depth. Isn't possible to make a mod that let's you choose when to keep the pumps running, and you don't loose depth?

[Sailor Steve]

The problem there is that there is no precise way to do it. You start to sink. You pump out water. You start to rise. You let water in. Striking a perfect balance would be difficult if not impossible.

This brings up the opposite question: Why would you want to sit still in one place while making as much noise as you would moving?

[smg13]

Why would I want to hover making noise? Uhm...maybe I am waiting in bad weather at periscope depth, for a convoy or a single ship to roll by... zero speed makes it easier to get a tracking solution, and the weather helps to cover up your noise.

Also... the pumps must be working when you are at the surface, even at zero speed. Why would you shut them out at periscope depth? Unless you want to save battery power or run silently, precise depth managemnt is very important in a sub. As a captain I wouldn't shut the pumps out.

But this is an academic argument... what I worried about is my game/mod installation being screwed up. If it is part of the mod (and "realistic") for the sub to start to take water and sink after a while, then that's ok. I'll learn to live with it.

[Sailor Steve]

We both seem to be missing each other's points.

Originally Posted by smg13

Why would I want to hover making noise? Uhm...maybe I am waiting in bad weather at periscope depth, for a convoy or a single ship to roll by... zero speed makes it easier to get a tracking solution, and the weather helps to cover up your noise.

In bad weather hovering would be even harder. Waves roll in a circular motion, and the the diameter of the circle is shown by the height of the waves on the surface. At periscope depth in bad weather the boat will be rolling just as heavily as it would on the surface. Pumping water out and letting it back in to maintain a balance would be impossible.

Also... the pumps must be working when you are at the surface, even at zero speed.

Not so. Water in the bilges would need to be pumped out on ocassion, but a surfaced submarine has positive bouyancy, just like a surface ship. Underwater the sub needs to maintain a precise neutral bouyancy to not rise or sink, which requires a touch that only a modern computerized pumping system can maintain.

Why would you shut them out at periscope depth? Unless you want to save battery power or run silently, precise depth managemnt is very important in a sub. As a captain I wouldn't shut the pumps out.

Pumps also require battery power, and as I've stated they are anything but silent. The point is that it is far easier to maintain depth with the dive planes and a little forward motion, and far quieter.

But this is an academic argument... what I worried about is my game/mod installation being screwed up. If it is part of the mod (and "realistic") for the sub to start to take water and sink after a while, then that's ok. I'll learn to live with it.

Yes, it's realistic. Aces Of The Deep had a wonderful little routine that made it so even at silent running you would start to sink, and the LI would tell you "Captain, cannot maintain depth without running the pumps." No game since 1994 has come close to the kind of detail that one had.

[smg13]

Well, Sailor Steve, thanks for taking the time to explain all of it. It is very intersting. It is nice to see how much SH3 has matured that we can have such a discussion.

[Sailor Steve]

Well, smg13, thanks for putting up with my anal-retentive devotion to literalism and minutiae. I didn't mean to go overboard. Sometimes it just happens. Sorry about that.

[JayDee]

Originally Posted by smg13

Why would I want to hover making noise? Uhm...maybe I am waiting in bad weather at periscope depth, for a convoy or a single ship to roll by...

In good weather, a very good LI was actually able to make the boat hover without making noise at periscope depth (with the periscope raised). If he got the neutral buoyancy "almost right" by +/- a few kg, when e.g. the boat slowly sank deeper, the periscope going down in the water would add to the displacement - to the point where the buoyancy is exactly neutral.

@Sailor Steve:

Underwater the sub needs to maintain a precise neutral bouyancy to not rise or sink, which requires a touch that only a modern computerized pumping system can maintain.

Not necessarily "modern" or "computerized", systems like that were developed during WWII by Friedrich Tuschka for a company called Askania (a kind of mechanical computer, called "Eiserner LI" or "iron LI"). They were mounted in U 555 for trials, and later in U 235, U 236, U 867, U 1017 and U 2511.
After the war, this (still mechanical) system was further developed and used in german Type 205, (I think) 206 and some 209 export boats, as well as in several french submarine classes, until they were replaced with modern electronic devices.

[Sailor Steve]

Originally Posted by JayDee

In good weather, a very good LI was actually able to make the boat hover without making noise at periscope depth (with the periscope raised). If he got the neutral buoyancy "almost right" by +/- a few kg, when e.g. the boat slowly sank deeper, the periscope going down in the water would add to the displacement - to the point where the buoyancy is exactly neutral.

I've seen that quoted elsewhere, but never the actual description. The only problem I can see with that method is that it means the periscope is up, and easy to spot, which doesn't exactly help with the avoiding detection part.

@Sailor Steve:

Not necessarily "modern" or "computerized", systems like that were developed during WWII by Friedrich Tuschka for a company called Askania (a kind of mechanical computer, called "Eiserner LI" or "iron LI"). They were mounted in U 555 for trials, and later in U 235, U 236, U 867, U 1017 and U 2511.
After the war, this (still mechanical) system was further developed and used in german Type 205, (I think) 206 and some 209 export boats, as well as in several french submarine classes, until they were replaced with modern electronic devices.

Interesting. Did this device actually balance the trim for hovering the boat? How long could depth be maintained without running the trim pumps? This is cool information.

[JayDee]

Originally Posted by Sailor Steve

Interesting. Did this device actually balance the trim for hovering the boat? How long could depth be maintained without running the trim pumps? This is cool information.

I had to look back in my literature... I try to translate the part:

For the new Bundesmarine submarines [Type 201 / 205], automatic depth control / hovering devices were developed by Tuschka Feinmechanik company, based on the last developments of Askania for the Kriegsmarine during WWII, working according to the principals of mechanical computers.
The device DT1 for automatic depth control kept the submarine at a given depth in all depths and at every speed, to disburden the crew during long continuing dived travel.
External interferences, like motion of the sea, currents etc. were counterbalanced by this device.

It was however more difficult to command a new depth via this device, because the pitch controller of the device counteracted the "new depth"-command, making depth changes quite slow.

The device contained a 5 kg pendulum to control the pitch of the submarine via the rear depth planes, and a diaphragm depth controller which controlled the depth via front and rear depth planes during slow travel. At higher speeds, the front depth planes were automatically retrieved, pitch and depth were controlled only via the rear depth planes. The actual mechanical computer for the depth and pitch controls contained multiplying devices, "sum levers" (sorry, no idea how to translate this) and "lead calculators" which computed the first and second derivation of the original sensor data, superimposing it on the original data.
The (adjustable) output signals of the device were assigned to the depth plane motors.

HDW commissioned Tuschka to develop a hovering device for the Type 205 submarines, which was completed in 1967/68. It was called DS 3 and should enable the boats to hover at a certain depth through flooding or pumping out water while the submarine was stationary.
This device was installed and tried upon U 11 and U 12, mounted starboard near the depth controlling device. It consisted of a target depth input device, diaphragm depth gauge, "lead calculator", solenoid valves for control air lines and diaphragm valves for flooding or pumping out water of the regulating tanks.

So I have to apologize: The true "hovering computer" did not come until the late 1960s (although it was still a mechanical device ), the "iron LI" was "only" controlling depth via the planes, which meant that the boat had to travel at least at slow speed.

Then again, if the boat was in a well trimmed condition, the "iron LI" (but a real LI as well) should have been able to do this also at slow speeds (silent running condition). Of course not, if the boat was damaged by depth charges and leaking.

EDIT: I may find some more info about the actual use of the Askania / Tuschka device in WWII Uboats in another book I have but right at the moment I am a little tired.. Tomorrow...

[smg13]

This might sound silly... but wouldn't it be possible to use a strong current and the planes to "hover", without using the engine propulsion? Would it be possible in the game?

[Sailor Steve]

@ JayDee: Thanks for supplying research. The more we learn about the technology of the time the more we can figure out what should or shouldn't be in the game. One can never have too much information.

Originally Posted by smg13

This might sound silly... but wouldn't it be possible to use a strong current and the planes to "hover", without using the engine propulsion? Would it be possible in the game?

No, because a submarine underwater is just like a balloon in the air. The boat will move with the current, so will in effect still be standing still. It's the same problem as you have with 'dead reckoning' navigation. Unless you have a shore reference you can't tell what direction the current is travelling or how fast, because you're travelling with it.