[REL] Additional Depth Charges v1.0

[tomfon]

Description

This simple mod introduces four additional types of depth charges for American and British destroyers, destroyer escorts, and frigates.
The type of depth charge deployed depends on the class of warship and, of course, on the progress of your career.

This mod does not introduce new 3D models for either the depth charge racks or the individual depth charge barrels.

The core of the mod originates from the NYGM supermod, which already includes an expansion that adds new types
of depth charges (the New Depth Charge Racks & New Depth Charges Mod). Permission to use this mod was kindly granted by Stiebler.
Based on that, I modified the relevant files and edited the .eqp files accordingly.

The mod introduces the following versions of depth charges:

---American DCs---

*Mark 6: The standard depth charge used by the U.S. Navy for most of the war had a terminal velocity of 2.4 m/s (meters per second),
or approximately 8 ft/s (feet per second).

*Mark 7 (Mod 1): This version was used early in the war and had a terminal velocity of 2.7 m/s (meters per second),
or approximately 9 ft/s (feet per second).

*Mark 9: The standard version used by U.S. Navy ships in the latter part of the war (from 1943 onward). Although it was lighter than the Mark 6 and Mark 7 types,
it was more powerful due to its explosive charge being Torpex instead of TNT. Its terminal velocity was 6.9 m/s (meters per second),
or approximately 22.7 ft/s (feet per second).

---British DCs---

*Mark VII: The standard depth charge used by the Royal Navy during the first three years of the war. It was relatively faster than the American Mark 6 and Mark 7,
with a terminal velocity of 3.0 m/s (meters per second), or approximately 9.9 ft/s (feet per second).

*Mark VII Heavy: This depth charge featured an improved sinking rate of 5.1 m/s (meters per second),
or approximately 16.8 ft/s (feet per second), thanks to a cast-iron weight attached to it.


Things that work (Technical info)

• Sink Rate/Terminal velocity. It works, however, there is a limitation. Read below.
  
  
• Depth precision. I left the depth variance unchanged at 15 meters. Depth charges will detonate randomly within this range.
  For example, if the AI sets the firing depth to 100 meters, the depth charge will explode at a random depth between 85 and 115 meters.
  
  
• Min and Max blast radius.
  
  Max radius:
  
  For the Mark 9, the depth variance is set to 25 meters; for the Mark 7, it is set to 30 meters; and for all other types, it is set to 20 meters.
  
  A single-hulled American WWI/WWII submarine would sustain minor to moderate damage if a
  depth charge containing 300 pounds (~136 kg) of TNT detonated at a distance of 50 to 100 feet
  (see ref. 1, §15-12). U-boats, being double-hulled, were known to withstand such blasts more
  effectively.
  
  With the depth precision set to 15 meters, a Mark 6 depth charge detonating 15 meters from a
  U-boat's hull would result in minor to moderate damage. If the detonation occurs 20 meters
  away, the U-boat would likely suffer little to no damage.
  
  Min radius:
  
  I specified a value of 4.5 meters (see ref. 5). This means that if your U-boat is
  within a 4.5-meter radius of the explosion's epicenter, the full amount of damage points
  will be applied.
  
  
• Shockwave effect. I reduced its strength, but this has no effect on the blast radius. Overall, it doesn't impact the performance of depth charges.

Limitations

1. As soon as a depth charge enters the water, it immediately reaches its terminal velocity. However, this is not realistic.

2. In reality, each depth charge had a maximum depth setting. In SH3, however, the maximum depth setting for all depth charges is set to 300 meters.
This means that all depth charges will detonate once they reach that depth, unless they have already exploded. Therefore, if you want to increase your
chances of surviving the war, it would be a nice idea to acquire a VIIC/41 U-boat, as soon as the type becomes available...


Compatibility & Installation

This mod is JSGME ready. It is compatible with GWX 'Gold' v3.0. It is also compatible with:

*Longer Repair Times v2.04 (LRT v2.04).
*Every option of "OLC 'Gold' MkII".

Installation instructions can be found in the README file.


Thanks & Acknowledgements

1. 'Stiebler' for allowing me to use specific files (read above).
2. 'skwas' for his S3D utility.
3. 'padi' for his 'Real ASW Mod' from which I derived useful information regarding the availability dates.


Interesting readings (References)

1.War Damage Report No.58 (US Hydrographic Office)
2.Depth Charges (The Pacific War Online Encyclopedia)
3.Mark 6 & Mark 7 Depth Charges
4.American & British ASW Weapons
5.Depth Charge (Wiki)


Further development

Although this mod includes most of the basic types of depth charges, there are other types I would like to add to the game.
Additionally, it would be great if I could find the time to expand the mod to accurately depict the number of depth charges carried by each type of destroyer and frigate. We'll see.


DOWNLOAD (SUBSIM)
DOWNLOAD (MEDIAFIRE)

[A6Intruder]

Hi,
could you please explain the differeces between your Mod and Real ASW Mod from Padi.
Thanks in forward.
Best regards

[tomfon]

Hello A6Intruder.

Well, my mod is compatible with GWX3. If you'd like to use padi's mod instead you should then edit all .eqp files so as to link the 3D model of each ship with the corresponding depth charge taking into account the type of the ship and the date.

There are some other differences regarding the properties of DCs (min & max efficiency radius,depth precision, hit points, shockwave effect).

What really troubled me was the efficiency radius and depth precision.

I will try and post my findings later.

[sublynx]

Very cool!

[Anvar1061]

Originally Posted by sublynx

Very cool!

Additional Depth Charges v1.0 (GWX3)

Real ASW Mod v.3 Beta 4

[tomfon]

@Anvar1061

In case you haven't read the description of the mod: It doesn't include new 3D models for the barrels.

So, please don't hijack the thread. If you don't like it, don't use it.

[Anvar1061]

Why do not you do better than v.2?

[rudewarrior]

I have been using Jungman's RealDC_4 mod to simulate changes in depth charges through the war. It very simply modifies the rate of descent and other features of the depth charges throughout the war to make it a little more challenging. I implement the changes through the war using SH3 Commander.

So the question I have is, would it be better to use this mod instead of RealDC_4? Also, I have some pretty good experience modding, so making the two mods compatible with my mod soup would take some work, so I am trying to figure out if it would be worth the time to make them compatible with each other and then my mod soup, etc. I think someone who is more familiar with the inner workings could give me a quick answer and I can dig into it more from there.

I can't find the link to Jungman's mod, but I have included the read me, so it might help answer questions about it.

RealDC_4 Mod   version 4.0  May 16, 2005   Jungman

This is a simple mod made for Silent Hunter III that changes 
the DepthCharge.zon and DepthCharge.sim files to simulate a more realistic DC model 
over the several years. From early to late war average values.

It was made for patch 1.3 but will work on all versions prior since 
this original file is not changed by any previous patches.

Please backup your original file!

Place the two files directory data/library replacing the original Depthcharge.zon and
DepthCharge.sim file.

"The two changes that are made is Maximum Range reduced from 40 meter to 10 meter,
and the Sinkng Speed increased from 3 m/s to 4.5 m/s war average."

Update for 4.0 depth precision put back to default 5 meters. I do not see that it has
much effect. Maximum blast radius reduced to 10 meters.


So Uboat should not be hurt at all if DC explosion is more than 10 meters away, but harder
to avoid the DC at depth below 50 meters to simulate the improved technology of later years. 
Sinking speed 3 m/s to 6 m/s at war end. I feel 4.5 m/s is good average. 

If you want only the reduced Maximum Blast Radius only (with default 3 m/s sink speed),
then only install the DepthCharge.zon file only.

The DepthCharge.sim will increase sink speed to 'Middle War' value of 4.5 m/s 
making them more chance to hit you at depth.

----------------------------------------------------------------------------
Change Log:
 
1) DepthCharge.zon 

The Mininum Range is still at default 4.5 meter.

The MinEF is still default 170 and MaxEF is still at default 230. (Strength of explosion).

The Maximum Range was reduced from default 40 meter to 10 meter. (version 4.0 change).

---------------------------------------------------------------------------
2) DepthCharge.sim

Sink rate increased from default 3 m/s to 4.5 m/s. (Early and Late War average. Version 4.0)

Depth Precision is back to default 5 meters. (version 4.0)
_________________________________________________________________________________________

Later updates will be done considering feedback.
 
I can change Strength, Sink speed, Precision (does not seem to do anything)
and Blast radius.

Happy Hunting!

[ivanov.ruslan]

Congratulations on the work of Tomfon!


Here is DC4 http://www.subsim.com/radioroom/down...o=file&id=3174

[tomfon]

@rudewarrior

Additional DCs includes a modified depthcharges.dat which has extra nodes added. Each of the extra node (as well as the original one) corresponds to a specific type of DC. The technical parameters of each DC can be found in the .sim and .zon files. So, basically, the mod adds new DCs to the game which will show up according to date and, of course, type of warship. Now every DC has its own specific attributes (terminal velocity, hit points etc.). This is the main difference between Real_DC and this mod. Therefore, i don't see any reason why merge these two mods. Instead, you could modify any of the values according to your taste.

@ivanov.rusian

Thanks!

[geosub1978]

The main problem with the DCs in the game is that they are set to explode at your depth which is not realistic, because it was (and still is more or less) impossible to determine the depth of the submarine. That's why they were set to explode with a depth pattern, unless it was known that the submarine was the previous moments at periscope depth and were set to shallow depth.

[rudewarrior]

Originally Posted by tomfon

So, basically, i don't see any reason why to merge the two mods. Instead, you could modify any of the values to your taste.

Thank you sir! You have confirmed exactly what I suspected! Additional Depth Charges it is!

Great work!

[Pablo]

Originally Posted by geosub1978

The main problem with the DCs in the game is that they are set to explode at your depth which is not realistic, because it was (and still is more or less) impossible to determine the depth of the submarine. That's why they were set to explode with a depth pattern, unless it was known that the submarine was the previous moments at periscope depth and were set to shallow depth.

Hi!

I'm guessing that the time required to develop algorithms, as well as the CPU time required to give AI ships the ability to use realistic depth patterns in a real-time simulation was probably more than the computers of 10 years ago could handle.

Pablo

[pathealey2]

Excellent work. Thank you - trying it now.

[tomfon]

Originally Posted by geosub1978

The main problem with the DCs in the game is that they are set to explode at your depth which is not realistic, because it was (and still is more or less) impossible to determine the depth of the submarine.

I wouldn't know about the efficiency of contemporary sonars and underwater detection systems, though it is quite interesting from a certain perspective.

Now, regarding the behavior of depth charges in SH3: Depth charges do detonate randomly at a given variance. There is a special entry for this in the .sim file called, "depth_precision". So, if you set a value of 5m then, if the AI sets the firing depth, say at 100m, the depth charge will detonate randomly between 95 and 105m.

In my opinion, the main problem with depth charges in SH3 is that the damage inflicted to the U-Boat from a certain type of DC depends exclusively on the distance of the U-boat from the epicenter of the explosion. For a proper simulation to take place other important factors should be taken into account too, such as the relative points of detonation, the fact that the damage is expected to be more effective when the detonation occurs under the hull (see reference 1, §15-10) and, of course, hydrostatic pressure.

Depth charges in SH3 (and why not, in SH4 too) don't/won't work the best way possible. But we do what we can.

Obviously, i'm asking for too much.