Submarine water dynamics

Dirk Gently · 12-04-18, 02:50 PM

EDIT: Test version of the WIP
DOWNLOAD v0.1

Use this thread for any further communication and feedback regarding this mod; http://subsim.com/radioroom/showthread.php?t=239358

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I wonder how much time and effort has been put into this from the modding community already?

I've been quite unhappy with how the subs behave in the water (surfaced) in SH3 for a long time and decided to take matters into my own hands. I started my investigation in the data\submarine\NSS_UboatXX directories, using VIIB as guinea pig due to the faster loading times in the Naval Academy.

The interesting values to tweak, as far as I've discovered so far, is located at "6:unit_Submarine". The first value I tried tweaking was fr_ratio (Gravity center). It defaults at 0,5 on all submarines (and probably all boats) and putting it further forward actually made the boat ride waves quite good and behave more like in real life. On the surface at least. Diving becomes a real problem because the boat is not in balance and the aft hangs lower in the water the further forward you set the balance. So while the main objective was passed with flying colours, the adverse effects forces this number to remain at default, 0,5 (midship).

I then started to fiddle with surface UD-drag (up and down-drag). All subs are default at 0,1 so I tweaked it to 0,2. The submarine stopped bobbing on the smaller waves and behaves much better than default. The submerged UD-drag is by default 0,15. Having the submerged drag slightly lower than the surface drag creates the more realistic effect that surfaced vessels bobs up faster than they bobs back down.

I tested reducing submerged drag to 0,1 and the result were even better from a surface perspective. I don't really know if this causes any huge difference in the submerged agility of the boat but I haven't noticed any huge difference.

I'm very happy with the results at least and if anyone else wants to test the tweaks and weigh in with opinions, it doesn't take a minute to tweak your submarine file (7B for ease of access) with the same to check out for yourself.

data\submarine\NSS_Uboat7b\NSS_Uboat7b.sim
6:unit_Submarine
7:unit_Submarine
unit_Ship
obj_Hydro
Surfaced -> drag -> UD = 0,2
Submerged -> drag -> UD = 0,1 (or default 0,15)

Dirk

JeromeHeretic · 12-04-18, 03:32 PM

Eh... this is problematic stuff. Look to this threads:
http://www.subsim.com/radioroom/showthread.php?t=143775
http://www.subsim.com/radioroom/showthread.php?t=204399

When i was trying to play with this i never get good results. Even if it was looking good for first view, i found some problems later.
For example even if i changed values for boats only a bit and everything was looking good, when i attacked some convoy and boats start zig-zaging, the whole convoy was breaked, boats was blocking each other and AI was not able do any inteligent corrections.

Dirk Gently · 12-04-18, 04:01 PM

The player sub doesn't run in convoys though...

Jeff-Groves · 12-04-18, 04:06 PM

It's your install Mate. Do whatever works for you!
I totally understand you mean only the Subs.

JeromeHeretic · 12-05-18, 06:06 AM

Quote:

Originally Posted by Dirk Gently

The player sub doesn't run in convoys though...

Sure... but i wrote it as an example of problems with only a bit changed values. I don't remember all problems i had, it's years ago.
I think in some supermod authors was playing with this parameters once (in LSH maybe?) and after this tuning sub was almost uncontrollable. Was almost impossible drive out from docks without crash and so...

ETR3(SS) · 12-05-18, 12:02 PM

Playing with settings and observing the results.

I'm playing with the aircraft in SH4 with the intent of making them historically accurate at the moment. You get some interesting results sometimes, like the H6K getting below its flight path and pulling straight up to get back to altitude. Aircraft stalls and plummets back into the ocean.

Dirk Gently · 12-08-18, 12:11 PM

I actually achieved more success than I hoped for.

What mainly did the trick was to increase Surface Up and Down drag to between 0,3 and 0,4 and place the ballast weight (balance point) slightly lower than Ubisoft has done, which is smack in the middle of the geometrical shape, and at the same time keeping the fore and aft balance intact to keep the vessel balanced. Submerged UD-drag remained as default to not mess with the most important part of the game, and that works out very well because the subs now behave like they actually want to stay afloat and at the same time look like they weight many tons, which they do.

While I was in there I also tweaked Mass, surface displacement and submerged displacement to historical metric ton values and tweaked diesel range and electrical range to historical values as well.

If there's any interest I could probably pack it as a mod file but if there's a lot of mod compatibility issues I'd rather write a tutorial.

12-04-18, 02:50 PM	#1
Dirk Gently Bosun Join Date: Nov 2018 Location: Norway Posts: 65 Downloads: 61 Uploads: 0	[WIP] Submarine Surface Riding Tweak EDIT: Test version of the WIP DOWNLOAD v0.1 Use this thread for any further communication and feedback regarding this mod; http://subsim.com/radioroom/showthread.php?t=239358 --------------------------------------------------------------------------------------------------------------- I wonder how much time and effort has been put into this from the modding community already? I've been quite unhappy with how the subs behave in the water (surfaced) in SH3 for a long time and decided to take matters into my own hands. I started my investigation in the data\submarine\NSS_UboatXX directories, using VIIB as guinea pig due to the faster loading times in the Naval Academy. The interesting values to tweak, as far as I've discovered so far, is located at "6:unit_Submarine". The first value I tried tweaking was fr_ratio (Gravity center). It defaults at 0,5 on all submarines (and probably all boats) and putting it further forward actually made the boat ride waves quite good and behave more like in real life. On the surface at least. Diving becomes a real problem because the boat is not in balance and the aft hangs lower in the water the further forward you set the balance. So while the main objective was passed with flying colours, the adverse effects forces this number to remain at default, 0,5 (midship). I then started to fiddle with surface UD-drag (up and down-drag). All subs are default at 0,1 so I tweaked it to 0,2. The submarine stopped bobbing on the smaller waves and behaves much better than default. The submerged UD-drag is by default 0,15. Having the submerged drag slightly lower than the surface drag creates the more realistic effect that surfaced vessels bobs up faster than they bobs back down. I tested reducing submerged drag to 0,1 and the result were even better from a surface perspective. I don't really know if this causes any huge difference in the submerged agility of the boat but I haven't noticed any huge difference. I'm very happy with the results at least and if anyone else wants to test the tweaks and weigh in with opinions, it doesn't take a minute to tweak your submarine file (7B for ease of access) with the same to check out for yourself. data\submarine\NSS_Uboat7b\NSS_Uboat7b.sim 6:unit_Submarine 7:unit_Submarine unit_Ship obj_Hydro Surfaced -> drag -> UD = 0,2 Submerged -> drag -> UD = 0,1 (or default 0,15) Dirk Last edited by Dirk Gently; 12-08-18 at 09:49 PM. Reason: This turned into a WIP mod

12-05-18, 12:02 PM	#6
ETR3(SS) Ocean Warrior Join Date: Dec 2007 Location: Between test depth and periscope depth Posts: 3,021 Downloads: 175 Uploads: 16	Playing with settings and observing the results. I'm playing with the aircraft in SH4 with the intent of making them historically accurate at the moment. You get some interesting results sometimes, like the H6K getting below its flight path and pulling straight up to get back to altitude. Aircraft stalls and plummets back into the ocean. __________________ USS Kentucky SSBN 737 (G) Comms Div 2003-2006 Qualified 19 November 03 Yes I was really on a submarine.

12-04-18, 03:32 PM	#2
JeromeHeretic Machinist's Mate Join Date: Jun 2011 Location: N 50 4 E 14 25 Posts: 127 Downloads: 266 Uploads: 0	Eh... this is problematic stuff. Look to this threads: http://www.subsim.com/radioroom/showthread.php?t=143775 http://www.subsim.com/radioroom/showthread.php?t=204399 When i was trying to play with this i never get good results. Even if it was looking good for first view, i found some problems later. For example even if i changed values for boats only a bit and everything was looking good, when i attacked some convoy and boats start zig-zaging, the whole convoy was breaked, boats was blocking each other and AI was not able do any inteligent corrections.

12-04-18, 04:01 PM	#3
Dirk Gently Bosun Join Date: Nov 2018 Location: Norway Posts: 65 Downloads: 61 Uploads: 0	The player sub doesn't run in convoys though...

12-04-18, 04:06 PM	#4
Jeff-Groves Village Idiot Join Date: Sep 2014 Posts: 5,319 Downloads: 130 Uploads: 0	It's your install Mate. Do whatever works for you! I totally understand you mean only the Subs.

12-08-18, 12:11 PM	#7
Dirk Gently Bosun Join Date: Nov 2018 Location: Norway Posts: 65 Downloads: 61 Uploads: 0	I actually achieved more success than I hoped for. What mainly did the trick was to increase Surface Up and Down drag to between 0,3 and 0,4 and place the ballast weight (balance point) slightly lower than Ubisoft has done, which is smack in the middle of the geometrical shape, and at the same time keeping the fore and aft balance intact to keep the vessel balanced. Submerged UD-drag remained as default to not mess with the most important part of the game, and that works out very well because the subs now behave like they actually want to stay afloat and at the same time look like they weight many tons, which they do. While I was in there I also tweaked Mass, surface displacement and submerged displacement to historical metric ton values and tweaked diesel range and electrical range to historical values as well. If there's any interest I could probably pack it as a mod file but if there's a lot of mod compatibility issues I'd rather write a tutorial.