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Old 09-26-2013, 03:30 PM   #1
Join Date: Jan 2010
Posts: 23
Downloads: 70
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Default [REL] U-boat Dynamics v1.1 for SH4 OM

This is a game play mod for Silent Hunter 4 with Operation Monsun.

Link to download page :

Installation instructions :

- Place " U-boat Dynamics for SH4 OM " into your Mods folder.
- Enable with JSGME.

If you are playing campaign mode you will need to start a new career for
this mod to work properly.

From the readme -

This mod does the following :

1 - Reduces u-boat acceleration.

To levels comparable with the Ship Acceleration Physics mod which is used
in Operation Monsun. Acceleration is still faster than real u-boats.

2 - Increases diving rates.

Crash dive times are as follows.
Time taken to reach 13m.

IIB/C 35 IID 25


IXB 35 IXC 37 IXD2 42

XXI 25 to 14m

3 - Adjusts submerged ranges and battery recharge times.

Low speed submerged ranges are increased.
Battery recharge times are reduced.

You will find propulsion specialists in your engine rooms.
They are required to make this mod work.

>>>>>>>>>> Note:
The type XXI and XXIII use the same " submerged range vs speed " curves
as the other u-boats.
This results in curves with a dip in them.
A graph of this is in the readme.

The submerged ranges at cruising speeds for the XXI and XXIII are close to realistic values.

XXI 630km at 5knots
XXIII 360km at 4knots

The ranges at speeds above 9 knots are greater than realistic values.

As a result of compromises the type XXI and XXIII have a faster battery recharge than I was aiming for. The XXI should take twice as long and the
XXIII should take four times as long.

Therefore if it took you one hour to recharge your batteries, and you wanted to simulate more realistic battery charging behaviour, you could continue running on the surface or schnorkeling for another hour in the XXI or another 3 hours in the XXIII.

4 - Adjusts turning circles

Type II's turning circle is smaller than type VII.
Type IX's turning circle is larger than type VII.
Full rudder reduces speed much faster than ordering full astern.
Use less than full rudder to maintain more speed in turns.

5 - Increases crush depths

U-boats would dive below 200m only in extreme circumstances.
Crush depths were deeper for all except type II.

6 - Applies the stock game's " destruction over time " model to the u-boat
when it exceeds crush depth.

To give a warning of impending doom and time to try to avoid it.

7 - Simulates a 6 knot silent speed for the type XXI and
a 4.5 knot silent speed for the type XXIII.

This only influences hydrophone detection, not sonar/asdic.

8 - Sets maximum speeds :

IIB 13.0 7.0 VIIB 17.9 8.0
IIC 12.0 7.0 VIIC 17.7 7.6
IID 12.7 7.4 VIID 16.7 7.3

IX 18.2 7.7 XXI 15.6 17.2
IXB 18.2 7.3 XXIII 9.7 12.5
IXC 18.3 7.3
IXD2 19.2 6.9

>>>>>>>>>Note: The UI knotmeter often indicates a higher than correct maximum speed.

Example: VIIC

Intended speed 17.7
Measured speed 17.67 18min 20sec for 10km
UI indicated speed 18.4

9 - This mod tries to maintain depth keeping below 180m.
Other things which may improve depth keeping are :

Levelling off at higher speed before switching to low speed.

A factor that seems to influence the rate of sinking below 180m is the rate of diving
as the u-boat passes the 180m mark.

In order to reduce the rate of sinking below 180m:
- level off just before 180m
- dive slowly past 180m
- once past 180m increase diving rate if required

Examples of changes to the VIIC u-boat.

without mod -----> with mod

) Reduced acceleration

surfaced 0 to 10 knots = 10 sec -----> 20 sec

surfaced 0 to 15 knots = 22 sec -----> 52 sec

submerged 2 to 6 knots = 14 sec -----> 34 sec

) Increased diving rates

crash dive time to 13 m = 26 sec -----> 27 sec

normal dive at flank

depth after 1 min = 14 m -----> 30 m

depth after 2 min = 45 m -----> 82 m

depth after 3 min = 90 m -----> 138 m

) submerged ranges and recharge times

submerged range at 2 knots = 121 km -----> 240 km

submerged range at 4 knots = 75 km -----> 105 km

submerged range at flank = 7 km -----> 9 km

time taken for full battery recharge = 26 hrs -----> 8 hrs

Change log :

v1.1 - reduced surfaced UD drag from 0.5 to 0.05 to increase pitching in rough seas.


Thanks to:

- Lurker_HLB3
and all the other contributors for creating Operation Monsun

- skwasjer
for S3D Silent 3ditor

- JSCones

Gute Jagd Kaleuns

Last edited by G7eT2; 10-20-2013 at 01:14 AM.
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Old 09-27-2013, 06:38 AM   #2
Pacific Aces Dev Team
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Excellent to see that there is still interest in this game & theater, many thanks man
One day I will return to sea ...
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Old 09-27-2013, 09:55 AM   #3
Sepp von Ch.
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I agree with hitman. Thank youG7eT2!
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Old 09-28-2013, 05:41 PM   #4
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Thank you for the thank yous.

Let me know if you find any problems or have any feedback.
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Old 04-12-2014, 09:52 AM   #5
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This is an excellent addition to OM and I am using it permanently.

Thanks a lot G7eT2!

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Old 04-12-2014, 10:00 AM   #6
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The only thing that perhaps needs to be reconsidered is the crush depth thing. Of course I am glad you made it possible to effectively dive below 210m without the instant death option. But now the boats dive a bit too deep for my taste. For example when I was sunk by an armed merchant once ( LOL), my VIIC reached over 360m before the hull was eventually destroyed.

As far as I can say, the criticial depth in SHIV and SHIII is too small, ca 200m. For VIIC boats, extending it to something like 250m with room towards 280m would be perfect. But I personally believe that almost every regular VIIC (not VIIC/41) would have been definitely crushed at ca 280 - 300m, and some even at 200m.

From :

"In the book "So war der U-Boot-Krieg" by Harald Busch there are reports of U 331 under Freiherr Hans-Diedrich von Tiesenhausen reaching 260 meters (853 feet) in an uncontrolled dive."

"Greatest depth reached by a uboat was around 320 meters (1050 feet) by U-175 (type IXC) on April 17 1943 after a depth charge attack by USCGC Spencer. Survivors of U 175 claim to have reached 320 meters (1050 feet) before correcting, surfacing and being abandoned but I would consider that "not surviving" as such."

With over 1000 specimens, this could be seen as indirect proof that 280-320m was the absolute limit. Some boats will have gone deeper than that, but none could survive it.

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Old 04-16-2014, 06:37 PM   #7
Join Date: Jan 2010
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Thanks for your comments GlobalExplorer.

I agree with you about the u-boat crush depths sometimes being unrealistic, and will try to give some explanation of the crushing behaviour in the mod.

Unfortunately the game engine only allows you to set the depth at which the u-boat begins to crush and the rate at which the damage occurs.

Ideally the game engine would also let you set a depth at which the hull fails instantly, but it does not.

In the mod I set the rate at which damage occurs so that you have a couple of minutes to try to ascend to a safer depth once you realise that you are taking damage.
Unfortunately if the u-boat is sinking fast this couple of minutes allows it to reach unrealistic depths, such as 360m, before the hull fails completely.
In making the mod I had to choose between having the hull fail quickly, which keeps the depth at which failure occurs within a smaller range, or having the hull fail more slowly which may give time to reach a shallower depth and survive. I think the second option is more fun as it allows for tense moments as the the crew takes action to try to save the boat. If the unrealistically deep hull failures, which sometimes occur as a result, are driving you nuts you might want to mod the mod as described below.

If you want to modify the crushing behaviour you can use Silent 3ditor to change the file :

Mods/U-boat Dynamics v1.1 for SH4 OM/Data/Submarine/NSS_Uboat7c/NSS_Uboat7c.zon ColisionableObject

and change the values for CrashDepth and CrashSpeed.

The CrashDepth value can be set so that:

CrashDepth x 0.7 = the depth at which the u-boat begins to take damage

The CrashSpeed value can be set closer to the Hit_Points value for a faster rate of damage.

You can also use notepad to make a change in the file:

Mods/U-boat Dynamics v1.1 for SH4 OM/Data/Submarine/NSS_Uboat7c/NSS_Uboat7c.CFG


This value sets the position of the red line on the depth gauge, and the depth at which you receive a warning, and the depth that the self preserving planesmen are reluctant to exceed.

With regards to your post about the 7c41_fixed_opmonsun mod on the download page, if you enable that mod first with JSGME and then U-boat dynamics after it both should work.

Good luck

Last edited by G7eT2; 04-19-2014 at 02:47 AM.
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