[tec] "bouyancy problem"

[Redlance88]

I understand it that at a depth below 250m or so it is very difficult to keep the sub from going to the bottom for good. Basically flank speed to maintain that depth or sink further and crush. My question is this, is this a bug or is this the way that they worked then. it's not as simple a question as it may seem. as a scuba diver, I know that near the surface one often has to add weight just to be able to stay underwater, but as you go deeper , you have to keep adding air to a Buoyancy control device to keep control of your depth and to keep from rapidly sinking. to me this sounds like the same thing is happening to the subs, and here is the kicker, after a certain depth there is no more volume for the trim tanks to keep the sub at the ordered depth , to to maintain depth you need up force from the dive plains. just like on the surface you need negative on the plains to force the sub underwater. ( I think ya can still dive a u-boat without them, but it would take a bit longer) the depths that this sort of effect would happen may be all wrong, but just thinking before it is (fixed) make sure it needs fixing.
I welcome comments from any more in the know than I.

[kylania]

The main problem with going below 250m was the whole 'bring crushed like an egg' thing.

There have been some bugs with holding depth below 180m though, apparently the same bug from SH4.

[vonTorpitz]

Interesting question. If what you are discussing actually was the case during the war, then the U-Boat commander would have always had to run his e-motors at flank speed in order keep the boat at an even depth. But if he is at over 200m depth then he is obviously evading an attack and would obviously not want to run so loudly for extended periods. Seems like a catch 22 and an interesting one if its true. However, I think its fairly unlikely because I'm fairly sure the trim and ballast tanks had a large role to play in bouyancy along side boat speed, probably enabling the commander to run silent.

[Sgtmonkeynads]

to to maintain depth you need up force from the dive plains. just like on the surface you need negative on the plains to force the sub underwater.

Has anyone ever checked the diveplanes in the game to see if they are trying to keep depth or are set in neutral when traveling forward at such a depth. Being in neutral would cause a crashdive of sorts at deep depths.

Makes you wonder if the diveplanes in the Game should be reversed at a certain level inorder to make this effect take place ? Very interesting !
I can't beleive all the stuff one can learn on this forum.

[Redlance88]

"There have been some bugs with holding depth below 180m though" Ooops, 180m then....

in regards to always having to run e- motors, no that's not what I am suggesting. What I am saying is that the deeper you go, the less effective trim tanks would be until a critical depth where you would have to be moving forward to maintain depth. before that you could try to establish a hover and just sit as a depth with no motors on. but beyond that depth you start to loose ground and need to move faster and faster through the water the deeper you go just to stay at a commanded depth, and if you were to slow down or stop you would sink, regardless of how much air you put into the trim tanks. now as I understand it Main ballast tanks are another story. they flood all the way at the surface just to get the boat under water. blowing the tanks at most any depth should create an Uncontrolled assent to the surface provided they are undamaged.
as always I am working with what I understand to be facts, and I may be totally misinformed on those facts.
My assumption here is that this effect is perhaps intentionally in the game, but perhaps too strong a force, or set too shallow, or we all just think it is set too shallow. I have had no luck finding any information on max hover (no dive plane effect) depth for German U boats of any kind.

[Trublion]

I would have no issues with not being able to keep buoyancy at 180m without help from the e-engines, however what bothers me if the fact that when ordering my sub to dive to 80m I end up at 150-160m. This make evading very tricky.
Oh and the dive planes are not at zero, but are indeed trying to get back to the set depth and by the look of it, my sub sinks from the rear... Is there any mass setting for the sub in the .zon file that could create this issue?

[TheBlobThing]

Are you guys sure it's not until 180m?

[kemeri]

May be such "bouyancy problem" could help to simplify the modding of the U-boat's dead stop depth keeping instability, as it has been done AFAR in GWX (positive dead stop) and in NYGM (negative dead stop). And to make it more complex and realistic then before .

[Kromus]

Originally Posted by Trublion

I would have no issues with not being able to keep buoyancy at 180m without help from the e-engines, however what bothers me if the fact that when ordering my sub to dive to 80m I end up at 150-160m. This make evading very tricky.
Oh and the dive planes are not at zero, but are indeed trying to get back to the set depth and by the look of it, my sub sinks from the rear... Is there any mass setting for the sub in the .zon file that could create this issue?

I did edit *.sim file for each sub to get stable sub at 140m w/o using engines (see my VIIB and C mod where I did change mainly "mass" values, sub could hold about 200m at 4 knots). The problem is that sub becomes very unresponsive to waves on surface - acts very much like "sub on rails".
So it seems you need to choose if you want more realistic surface behavior or underwater depth holding. I really want to know if theres some other workaround.

[Trublion]

It makes sense, I have been using a mod for more realistic surface behavior...