SH3's flawed sub physics?[A request]
 

I just found out that if the Uboat doesn't have sufficient forward momentum while submerged i.e, the speed is very low like 1 or 2 knots, the U-boat will sink slowly but it sinks.

The significance of this is that this means we would not be able to order speed less than Ahead slow which is about 3 knots i.e, silent running is actually not visible in SH3 game world.

Has anybody noticed this? Is there some way to fix this submerged slowly sinking behavior while moving at very slow speeds?

You haven't by any chance interrupted a crash dive before you observed that behaviour? Because interrupted crash dives cause this behaviour, the speed doesn't really matter I think.

Hmm I don't think I ordered crash dive the last time I tried this out. Ordering less than 3 knots like 2 or 1 knots to simulate silent running would cause our U-boats to sink slowly. You can try to order all stop while submerged(preferabbly at some deep depths like 200m) and you'll notice that your sub will slowly sink to the bottom during all stop. It will start to sink at speed below 3 knots or at ordered speed below ahead slow.

Its been known about for a while, and is has also been corrected in the past (modded) - but, its certainly not popular with everyone as it makes hunting much harder.
Another boyancy aspect not modelled is that most WW2 sub crews had to fight the controls somewhat after conducting a submerged torpedo attack in order to prevent the sub from breaking the surface due to the sudden loss of wieght.
The early British U-class subs had big problems with this, in fact is was so bad that it led to the 2 external tubes being removed from later versions of the sub.

Hmm I've never noticed behaviour like this, with GWX not at all because of the positive bouyancy mod, and not in stock SH3 either, although I would've liked to see it like it was in AOD, atleast under silent running, where the boat slowly began to sink after some time in silent running.

As I recall, there is only one mod that models negative bouyancy. (NYGM)

Using NYGM you must keep a speed of two knots to keep from sinking.

Stock SH3 and other mods use either neutral or positive bouyancy.

Castout, the problem you describe is not related to/does not occur in Stock Sh3.

(Also, if you sub has been damaged and is slowly sinking... this is normal due to flooding/extra water weight.)

Ju_88 you said it has been corrected in mods before, could you point me to at least one? I hate it when my sub starts to sink everytime I try to simulate a silent running.

Yes I'm aware that in RL the boat would try to compansate for loss weight after launching its eel(s) I do not expect a game physics to be that accurate but this incapability to simulate silent running is really fundamental imo especially when DDs are going to detect(hear) our boat much harder if we order a very slow speed. It's just that our boat refuses to float unless it's moving at a certain minimum speed which is totally unrealistic imo. Makes me feel like i'm flying not sailing an underwater craft:damn:

@Kpt Lehmann is it true? it doesn't occur in stock SH3? Okay let me play test this further.

Yes it is true. In un-moddified stock SH3 version 1.4b, with an undamage U-boat you can come to "All-Stop" and maintain whatever depth you choose.

What is truely needed to represent historical accuracy is the ability of the player to set variable bouyancy, and for compressed air to be used gradually in the effort to maintain a given depth.
This is not possible in SH3. ("not possible" is usually not in my vocabulary)

Yes you're right Kpt Lehmann in stock SH3 you can at least with type IX and type VIIB to maintain depth with very low speeds or at all stop at any depths.


Maybe my first post was specific to type VIIC/41 or I was interrupting a crash dive order.

Yea too bad SH3 doesn't take into account the compressed air used during depth changing. That would be so very cool. Anyone tried to mod this:D?

I have another question more like an idea on modding 'rig for silent running' command, a simple one really but I think I prfer to start a whole new thread for it.

When I said corrected - I meant negative/positive boyency was added - in stock Sh3 the uboat can hover like a humming bird, just as the Kpt already pointed out.

Yea Ju_88 sorry for my false alarm everybody

Why would that be unrealistic? At the beginning of the patrol, and every chance they got during it they did re-trim the boat, but any time you're in a position to need to run silent you have likely
1) Fired torpedoes, and

2) Been consuming food, water and fuel without time for a new trim dive.

Both of which will leave the boat likely to either rise or sink. This can be easily countered with the pumps, but when 'Silent Running' the pumps have to be off. In World War Two it was nearly impossible to get a boat to hover without moving, especially in a combat situation. One of the beauties of good old Aces Of the Deep was that after silent running for awhile the Chief would tell you "Captain, it is impossible to maintain depth without running the pumps".

I think the sinking is one of the most realistic mods.

Yes, it's true. In stock SH3 you can hover the boat forever.

Really? Thanks for the history lesson. On my second thoughts I'm actually happy with it sinking...no pumps eh?

Now if the modders can make the interior lights stay turned off for awhile after a close depth charging........"We are at 220m Sir!!!!!!!"
Any way to make the lights off much longer? GUI doesn't need to be messed with. They did already have flashlights. Hey this may be the topic of another thread. I'll make one for this.

Anybody worked on the compressed air mod stuff?

I do recall
 

I do recall reading years ago that subs in WWII had to keep a slight forward movement going in order to maintain a stable depth level. Part of holding to a depth was done by the use of the diving planes which required at a minimum a slight forward motion. I'd have to go back through all the U-boat books I ever read to find the quote. But I recall the words of it everytime I am setting motionless at periscope depth. I am always thinking: this would be impossible in real life.

In RL this behavior was caused by small leaks produced by various causes, damages etc. in the lower part of the hull ( italian "sentina") Also in Das Boot, Buccheim wrote that even during the dive, the U boot had to expell water in excess from the boat