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Old 12-04-2018, 02:50 PM   #1
Dirk Gently
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Default [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

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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

Last edited by Dirk Gently; 12-08-2018 at 09:49 PM. Reason: This turned into a WIP mod
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Old 12-04-2018, 03:32 PM   #2
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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.
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Old 12-04-2018, 04:01 PM   #3
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The player sub doesn't run in convoys though...
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Old 12-04-2018, 04:06 PM   #4
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It's your install Mate. Do whatever works for you!
I totally understand you mean only the Subs.
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Old 12-05-2018, 06:06 AM   #5
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Quote:
Originally Posted by Dirk Gently View Post
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...
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Old 12-05-2018, 12:02 PM   #6
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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.
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Old 12-08-2018, 12:11 PM   #7
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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.
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Old 12-08-2018, 02:15 PM   #8
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Quote:
Originally Posted by Dirk Gently View Post
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.
please do it.
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Old 12-08-2018, 06:06 PM   #9
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This is an obsession, really.

I found a real VII manual online and found the exact Gravity Centre of the ballast on a drawing. A quick X-formula could translate the drawing to real world measurement, which turned out to be 2,796m from the bottom of the keel.

This actually messed up my previous tweaks a bit but the first tests of a "new" tweak is really promising. I've managed to get the sub to keep periscope depth at 1 knot and stationary and at the same time having waves influencing the stability of the periscope realistically.

Since there's no real physics involved in acceleration of the submarines from the propellers at the aft, the bow won't naturally rise from acceleration like in real life, so the aft is unnaturally popping up and the mid section becomes too high in the water as a result.

Due to these limitations the best I can achieve is to make the subs appear to actually have weight and avoid these awkward 10 meter dives in bad weather while maintaining the maneuverability of the sub. The main feature of this last discovery is that the side-rolling becomes much more realistic with the G point placed more or less spot on where it actually was. Pushing down the stern is not achievable without making the sub dive awkwardly and become unbalanced while submerged, sadly.

I'll post an update later tonight or tomorrow.

PS. I'm a math teacher so I trust my calculations but if anyone is curious I can upload a screenshot with measurements and calculations.

PPS. I'm also aware that realistic weight and measurements won't translate realistically into a body of water that isn't behaving 100% realistically but as long as it gets better than the starting point, and I'm enjoying the work, I'm going for it.
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Old 12-08-2018, 08:13 PM   #10
JeromeHeretic
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Do both. Mod for people which will like it (or just want try it and when will like it, merge it to their mods) and do manual, so people can easy implement it into their work.
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Old 12-08-2018, 09:34 PM   #11
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Use this thread for any further communication and feedback regarding this mod; http://subsim.com/radioroom/showthread.php?t=239358

Proof of concept mod.

This is only the VIIB as it's the only Sub I've fully tested so far.

All weights and displacement changed from Long Tons to US tons assuming that's what the game uses since it also seem to be using US miles for range.

I'll explain in further details exactly what the final tweaks are and I'd appreciate feedback on this one. During testing the boat never went below 6 meters in bad weather. It cuts through some waves while riding others, depending on whether she's rising or falling when she hits the wave. I managed to keep the stern lower than default and make the bow rise to keep the boat afloat rather than going for those infamous 10m dives with crew on deck. You'll rarely see the propellers out of the water.

It's worth noting that I've only tested the mod with MEPv6 installed, which I believe affects waves somewhat.

Warning: The mod only affects a tiny .sim file in the VIIB Submarine directory

DOWNLOAD v0.1

Last edited by Dirk Gently; 12-08-2018 at 09:48 PM.
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Old 12-09-2018, 04:02 AM   #12
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Just a note: It is possible, that they are not using american miles, but SH3 nautical miles. SH3 is using "flat mercator world" in which 1 nautical mile = not 1852 m, but 2000 m.
So it means, that in SH3 world 2000 m = 1" of longitude and latitude.
Im sure about it, so u can try it in your calculations if this value makes sense...


And THX for this mod. I hope i check it in few days.
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Old 12-09-2018, 05:38 AM   #13
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Thanks for reply, Jerome. I'll look into that.

Please use the other thread; http://subsim.com/radioroom/showthread.php?t=239358
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