[REQ] Maintain depth fix

[Nicolas]

Hello, you can copy the drag etc values from VIIC to VIIA/B to correct sinking, i don't know deeper than 200 what happens.

[andycaccia]

Originally Posted by TheDarkWraith

maybe this will help you all figure it out (also tells you what put on water does):

HydroCtrl.cpp.The object's front-rear drag coef...FR..The object's up-down drag coef..UD..The object's left-right drag coef...LR..The object's drag (water resistance) coefs [F=C*v^2]....The object's draught [m]. If 0, then the geometric bounding box height is taken.....draught.....The object's displacement [Tons]. If 0 then it is automaticaly computed.....displacement....The object's submerged parameters...Submerged.......The object's draught [m]. If 0, then it is taken from the object's global position......The object's displacement [Tons]. If 0 then the object's mass is taken..The object's surfaced parameters....Surfaced....Put the hydro object on the water at the surfaced draught...bool....put_on_water........Gravity center horizontal position [>0]. 1=FRONT, 0.5=MIDDLE, 0=REAR....fr_ratio........Gravity center height from the object's bottom [m]. If 0, then the half of geometric bounding box is taken..gc_height...The object's mass [Tons]. If 0, then the object's surfaced displacement is taken....mass....Display the object's submerged draught..SD..Display the object's gravity center.....GC..Display the object's parameters.....params..Debug display settings..Debug...Hydro controller: controlls an object that can float....obj_Hydro...hull

Thank you, but those descriptions are the same displayed by goblineditor, so I guess everybody already knows them. My question was about the actual effects it could have in game. but don't worry: I found the answer on my own: basically nothing changes if you turn this off.

[andycaccia]

Originally Posted by Nicolas

Hello, you can copy the drag etc values from VIIC to VIIA/B to correct sinking, i don't know deeper than 200 what happens.

I fear it's not that easy. I've done this but it doesn't work for me. Cloning a VIIC sim file still leaves the sinking effect. Does it work for you?

[Nicolas]

Yes it worked, i opened the .gr2 file and merged it with the .sim then i copied all the values that i thought was relative to depth keeping including mass displacement surfaced and submerged, drag.

[andycaccia]

Originally Posted by Nicolas

Yes it worked, i opened the .gr2 file and merged it with the .sim then i copied all the values that i thought was relative to depth keeping including mass displacement surfaced and submerged, drag.

I see, I have done the same. This solved the porblem relative to the VIIB which
was unable to keep the ordered depth (it goes 4 meters lower than ordered at 40m depth and slightly less ar shallower depths) but still leaves the slow sinking effect. For example, can you keep your boat stable at 180m at very low speed with your method? I remember the VIIcs sinking down anyway...

[eon850aye]

Originally Posted by andycaccia

under "E_propulsion" set the "eng_power" value to 1500 (which was the real total power output of the electric motors anyway 750+750).

Sorry to be a stickler for historic specification, and sorry for kicking you repeatedly whilst down, but strictly speaking, this isn't true.
I was in the middle of moving house when SH5 was released & my typeVII bible (Anatomy of the Ship - The Type VII U-boat by David Westwood, taken from his Ph.D thesis on German U-boats from 1935-45) was packed away, dug it out this morning...
...it says

Type VIIa
2 BBC (Brown Boveri & Co) GG UB 720/8 electric motors totalling 750shp

Type VIIb
2 AEG GU 460/8-276 electric motors totalling 750shp

Type VIIc
U's 69-72, 89, 93-98, 201-212, 235-300, 331-348, 351-374, 431-450, 731-750, 1051-1058, 1063, 1068, 1191-1214, 1271-1285, 1301-1312;
2 AEG GU 460/8-276 electric motors

U's 77-82, 88, 90-92, 99, 100, 132-136, 401, 451, 452, 551-650, 751, 821-840, 929-936, 951-1050;
2 BBC (Brown Boveri & Co) GG UB 720/8 electric motors

U's 301-330, 375-400, 701-730, 752-782, 1131, 1132;
2 GL (Garbe, Lahmeyer) RP 137/c electric motors

U's 349, 350, 402-430, 453-458, 465-486, 651-698, 901-912, 921-928, 1101-1110, 1161-1170;
2 SSW (Siemens-Schuckert-Werke) GU 343/38-8 electric motors
Output totalled 750shp in all cases

Type VIId & f
2 AEG GU 460/8-276 electric motors totalling 750shp

Whether or not it makes a whole lot of difference I dont' know, but I am gonna mess around with this myself this weekend (no football on this weekend - english premiership)
Am also going to look at the displacements as a few of those seem to wrong. Well not wrong so to speak, they mostly seem to be dry weights, no water/fuel, unmanned and unloaded, see if those play any part.
I'll let you know of anything significant andycaccia.

[andycaccia]

Originally Posted by eon850aye

Sorry to be a stickler for historic specification, and sorry for kicking you repeatedly whilst down, but strictly speaking, this isn't true.
I was in the middle of moving house when SH5 was released & my typeVII bible (Anatomy of the Ship - The Type VII U-boat by David Westwood, taken from his Ph.D thesis on German U-boats from 1935-45) was packed away, dug it out this morning...
...it says

Type VIIa
2 BBC (Brown Boveri & Co) GG UB 720/8 electric motors totalling 750shp

Type VIIb
2 AEG GU 460/8-276 electric motors totalling 750shp

Type VIIc
U's 69-72, 89, 93-98, 201-212, 235-300, 331-348, 351-374, 431-450, 731-750, 1051-1058, 1063, 1068, 1191-1214, 1271-1285, 1301-1312;
2 AEG GU 460/8-276 electric motors

U's 77-82, 88, 90-92, 99, 100, 132-136, 401, 451, 452, 551-650, 751, 821-840, 929-936, 951-1050;
2 BBC (Brown Boveri & Co) GG UB 720/8 electric motors

U's 301-330, 375-400, 701-730, 752-782, 1131, 1132;
2 GL (Garbe, Lahmeyer) RP 137/c electric motors

U's 349, 350, 402-430, 453-458, 465-486, 651-698, 901-912, 921-928, 1101-1110, 1161-1170;
2 SSW (Siemens-Schuckert-Werke) GU 343/38-8 electric motors
Output totalled 750shp in all cases

Type VIId & f
2 AEG GU 460/8-276 electric motors totalling 750shp

Whether or not it makes a whole lot of difference I dont' know, but I am gonna mess around with this myself this weekend (no football on this weekend - english premiership)
Am also going to look at the displacements as a few of those seem to wrong. Well not wrong so to speak, they mostly seem to be dry weights, no water/fuel, unmanned and unloaded, see if those play any part.
I'll let you know of anything significant andycaccia.

I saw (almost) the same data on wikipedia, and I guess they're correct. Anyway, changing the power output in the .sim files doesn't affect gaming. I only used that value to make sure the boat would have the necessary thrust to compensate the increased rudder efficiency.

And I remind you that I was not looking for historical specifications, instead I was working to find a solution for the siniking effect. Data about mass and displacements were correct, but the submarines had unacceptable behaviour while submerged..so I had to make changes. Thank you for your help, tell me if you find some solution for this. Good luck

[eon850aye]

Originally Posted by andycaccia

And I remind you that I was not looking for historical specifications, instead I was working to find a solution for the siniking effect. Data about mass and displacements were correct, but the submarines had unacceptable behaviour while submerged..so I had to make changes. Thank you for your help, tell me if you find some solution for this. Good luck

Oh I know, sux big, not much point in ordering 190m if your either not going to make it that far or just dive straight through
Well just finished running comprehensive depth tests using the UHS_1.4 mod, down to 200m(7a,b,c) & 250m(7c/41) running at Ahead Slow & Flank speeds, and to my results the 7b is the best, although still shallow at both speeds, depths are maintained closest when running at flank, but thats no good when your trying to evade & escape a bunch of sub hungry destroyers.
I'll run the same tests again tomorrow using your suggested values, I'll also take a look at HanSolos Improved Waves, Pitch and Roll mod which also says its cures the maintaining depth problem, but I have yet to try it.
I'll pass on todays results to ddrgn, see if it matches up with his results, if he wants them & once I've typed them up.
Will let you as soon as.

[andycaccia]

Originally Posted by eon850aye

Oh I know, sux big, not much point in ordering 190m if your either not going to make it that far or just dive straight through
Well just finished running comprehensive depth tests using the UHS_1.4 mod, down to 200m(7a,b,c) & 250m(7c/41) running at Ahead Slow & Flank speeds, and to my results the 7b is the best, although still shallow at both speeds, depths are maintained closest when running at flank, but thats no good when your trying to evade & escape a bunch of sub hungry destroyers.
I'll run the same tests again tomorrow using your suggested values, I'll also take a look at HanSolos Improved Waves, Pitch and Roll mod which also says its cures the maintaining depth problem, but I have yet to try it.
I'll pass on todays results to ddrgn, see if it matches up with his results, if he wants them & once I've typed them up.
Will let you as soon as.

Keep on mind my friend that with my values you'll have very fast diving times and a really terrible submarine on rails effect in stormy seas. Depth keepig capabilities, instead, are very good on all tweaked models.

Cheers.

Hi

I was wondering just how accurate uboat diving could have been. I know the pressure gauges would have been calibrated as the valves where etc, but I wonder if that is the problem, maybe uboat diving was achieved more by the seat of your pants stuff.

How accurate would the +/- uboat depth itself been beyond the 90 meter mark. Say to reach 150 meters quickly from the surface, how long would it have taken to trim the boat to that depth, would the boat have over dived the required 150 meter depth and then power on to get upto 150 meters, Im thinking about the initial water intake to submerge a boat and how they attained the correct quantites of water to achieve a depth of 150 meters quickly. It seems to me that a boat had to power through the water at any depth else it sank, the deeper it went the hander the balance between displacement and silent speed

Today with digital flow meters that can accurately measure water quanties and valves that are instant air controlled devices, I can understand how a boat can hover or get to a particular depth very very quickly, even at critical depths. The Uboat would not have enjoyed this technology and accurate diving depth would have still been critical hense to 90 meter limit on the depth gauge. When designing the VII/41 they had trouble with the boats displacement of extra weight due to hull thickness, this forced the designers to find ways of reducing the boats weight with internal savings, something critical here.

I wonder if the programmers where trying to reflect a more realistic diving experiance rather than the spot on diving of SH3/4. Ok I know it's note right as is and I hope you get it right, but spot on, mmmmm.

thanks for your effort sid

[Vanilla]

Originally Posted by sidslotm

... It seems to me that a boat had to power through the water at any depth else it sank, the deeper it went the hander the balance between displacement and silent speed
...

They easily pumped water in and out of diving and other tanks while submerged to achieve neutral buoyancy and longtitudinal stability. Otherwise how would you control even slight flooding? And think of all excess power, battery capacity and noise you would need if you could not control your buoyancy to precise level. Even if you don't have a perfectly calibrated valve you could achieve desired buoyancy by trial and error.

AFAIK they would normally keep slightly positive buoyancy, so under low RPMs the boat would slowly float to the surface - directly opposite of what we see in the game.

They easily pumped water in and out of diving and other tanks while submerged to achieve neutral buoyancy and longtitudinal stability. Otherwise how would you control even slight flooding? And think of all excess power, battery capacity and noise you would need if you could not control your buoyancy to precise level. Even if you don't have a perfectly calibrated valve you could achieve desired buoyancy by trial and error.

Yes I recon thats correct, I was thinking about the time it took to trim the boat after diving beyond the 90 meter recommended depth. Beyond 90 meters in 1930s the engineers manual for diving a boat would be void surely. I read recently they lost a uboat because someone flushed the toilet incorrectly while submergered.

I just see the equation of (time ( water quantity ( water pressure ( speed of boat )))), being harder to control at 150 meters than previous versions of silent hunter sugested.

sid

[andycaccia]

Surely depth control needed a lot of care and tuning on such submarines, but a neutral buoyancy (more or less) could be obtained, that's for sure. And when you are almost neutral it's easy to keep the desired depth with speed and diving planes.

The game has a bug. There is no doubt about that.

[Vanilla]

Just checked the fleet boat manual and some other sources, if I get it right, it is even easier - the boat was trimmed to neutral buoyancy before the actual dive, that is before the boat even was in the combat zone, during a test-dive. So when you are on the surface you have main ballast tanks empty and have positive buoyancy. When you need to dive you just flood your MBTs and with them flooded you have pre-trimmed neutral buoyancy so you can simply use dive-planes to easily and precisely control your depth, fine-trimming when needed. If it really was an emergency you could flood your negative tanks so the boot would get negative buoyancy and sink, but those were blown empty at depth of 9-11m already.

And if neutral bouyancy was pre-trimmed then there would be no problem with depth control through full diving range at all times.

[eon850aye]

@ andycaccia,

so things are looking up for the Type VIIb with regards to this rail look and keeping depth at slow speed.
It's not perfect, nothing ever is, but its getting there.
The boat has a nice pitch and roll on the surface now, and will maintain depth down to 200m. Unfortunately it is alittle shallow down to approx 110-112m, but only between 0.5-1m.

Last test results; speed at 2 knots
Depth Ordered.....Depth Achieved.....Depth Maintained
Periscope(12m)...........12m....................ye s
.....50m...................49.5m.................. .yes
.....88m....................87m................... .yes
....100m....................99m................... yes
....111m...................110m................... yes
....115m...................115m................... yes
....125m...................125m................... yes
....137m...................137m................... yes
....163m...................163m................... yes
....182m...................182m................... yes
....200m..................200.2m.................. yes

At 200m, when motors were switched off, you got that slow sinking as you mentioned before, but power on again and it stops and levels out.

So far I'm pleased with the results.

It still needs alittle fine tuning, and Im waiting to hear back from TheDarkWraith about something, but I will let you know as soon as I have something more solid for you to look at