# Thread: Depth Charges Lethal Radius and Sub Damage........... | Forums

1. In SH2, depth cherges lethal radius was so biggest than in the historical real life......

ABOUT LETHAL RADIUS :

Looking into the SH2 files, and reading about historical values, I found the Lethal Radius for
all Depth Charges in the game are so exaggerated.........

Looking into the historical technical data, we can found in some places the Lethal radius
for a 420 lbs./136 kg. TNT depth charge was between 5 and 6 meters.

In another places do the mention of the early 420 lbs./ 136 kg. TNT depth charges has a
lethal radius of about 4.1 m.

In more detailed level places we can found the Lethal Radius of a Mark III, a 420 lbs.
(136 kg. TNT) depth charge has a lethal radius of about 4.3 m.

A derivate of this was the Mark VII 420 lbs/130 kg, TNT wich had a lethal radius of
about 6.1 m, (according as declared).

An d the Mark VII Heavy 420 lbs/132 kg TNT with moe sink rate, with a lethal radius of
about 6.1 m, (according as declared).

This depth charge was filled with Minol high explosive, increasing its lethal radius up to
7.9 m, (according as declared).

As we can see........ lethal radius for a 420 lbs/ 130kg-136kg TNT vary between 4.1 m
and 6.1 m.

It is really so diferent of what we can found into the sim files............

In the sim, lethal radius was so exaggerate.........

You can found for a depth charge of 429lbs./ 130kg. of explosive a letal radius
of 50 meters !!

It is 164 feet !! More than 10 times higher than the real value!!

Plus........

Damege in SH2 was modeled in acordance with the sub tonage.........

What it means ?

A sub with more tonage will be more resitent to depth cherges and this is not true at all.........

Logic saids us, the more resistant hull will be that from the more deepest sub.......

The sub wich its maximum navigation depth is bigger will be the mos resitant.........

In SH 2 it is not true, the type IX hull has a maximun operative depth of 200m but is to much resistant to depth charges
than a type VII hull, with 260 m of maximun operative depth.........

In consecuence, the stronger hull is the more easy to sink.........

Many persons made depth charges chanes in SH2, me included..........

I correct the lethal radius to real historical values, and solve the hull resistance, changing the submerged tonnage of the subs, to put the sub's resistence in accordance with the hull maximun operative depth not the tonnage..........

Will be great in SH 3 to have real historical Depth Charges Lethal Radius, and sub's hulls resistance in accordance with the hull capacity to resist pressure depth......... not sub's tonnage.

Best regards, Red.

P D :

Some fonts of information........

FONTS OF INFORMATION :

http://www.warships1.com/Weapons/

http://www.warships1.com/Weapons/WAMUS_ASW.htm

http://www.warships1.com/Weapons/WAMUS_Mines.htm

http://www.warships1.com/Weapons/WAMRussian_ASW.htm

http://www.warships1.com/Weapons/WAMRussian_Mines.htm

http://www.warships1.com/Weapons/WAMBR_ASW.htm

http://www.warships1.com/Weapons/WAMBR_Mines.htm

http://www.warships1.com/Weapons/WAMGER_ASW.htm

http://www.warships1.com/Weapons/WAMGER_Mines.htm

http://www.warships1.com/Weapons/WAMJAP_ASW.htm

http://www.warships1.com/Weapons/WAMJAP_Mines.htm

http://www.njahof.org/jager/ship_articles.html

http://mscmga.ms.ic.ac.uk/jeb/or/intro.html

http://www.gwpda.org/naval/br1669.htm

http://uboat.net/boats/u427.htm

http://www.forces.gc.ca/site/fourth_...03/06_fd_e.htm

______________________________
.

.
The Ancient History of the Submarine
"Subgenesis"

Manual TDC
"HTDC Tutorial"
.

2. In SH2, depth cherges lethal radius was so biggest than in the historical real life......

ABOUT LETHAL RADIUS :

Looking into the SH2 files, and reading about historical values, I found the Lethal Radius for
all Depth Charges in the game are so exaggerated.........

Looking into the historical technical data, we can found in some places the Lethal radius
for a 420 lbs./136 kg. TNT depth charge was between 5 and 6 meters.

In another places do the mention of the early 420 lbs./ 136 kg. TNT depth charges has a
lethal radius of about 4.1 m.

In more detailed level places we can found the Lethal Radius of a Mark III, a 420 lbs.
(136 kg. TNT) depth charge has a lethal radius of about 4.3 m.

A derivate of this was the Mark VII 420 lbs/130 kg, TNT wich had a lethal radius of
about 6.1 m, (according as declared).

An d the Mark VII Heavy 420 lbs/132 kg TNT with moe sink rate, with a lethal radius of
about 6.1 m, (according as declared).

This depth charge was filled with Minol high explosive, increasing its lethal radius up to
7.9 m, (according as declared).

As we can see........ lethal radius for a 420 lbs/ 130kg-136kg TNT vary between 4.1 m
and 6.1 m.

It is really so diferent of what we can found into the sim files............

In the sim, lethal radius was so exaggerate.........

You can found for a depth charge of 429lbs./ 130kg. of explosive a letal radius
of 50 meters !!

It is 164 feet !! More than 10 times higher than the real value!!

Plus........

Damege in SH2 was modeled in acordance with the sub tonage.........

What it means ?

A sub with more tonage will be more resitent to depth cherges and this is not true at all.........

Logic saids us, the more resistant hull will be that from the more deepest sub.......

The sub wich its maximum navigation depth is bigger will be the mos resitant.........

In SH 2 it is not true, the type IX hull has a maximun operative depth of 200m but is to much resistant to depth charges
than a type VII hull, with 260 m of maximun operative depth.........

In consecuence, the stronger hull is the more easy to sink.........

Many persons made depth charges chanes in SH2, me included..........

I correct the lethal radius to real historical values, and solve the hull resistance, changing the submerged tonnage of the subs, to put the sub's resistence in accordance with the hull maximun operative depth not the tonnage..........

Will be great in SH 3 to have real historical Depth Charges Lethal Radius, and sub's hulls resistance in accordance with the hull capacity to resist pressure depth......... not sub's tonnage.

Best regards, Red.

P D :

Some fonts of information........

FONTS OF INFORMATION :

http://www.warships1.com/Weapons/

http://www.warships1.com/Weapons/WAMUS_ASW.htm

http://www.warships1.com/Weapons/WAMUS_Mines.htm

http://www.warships1.com/Weapons/WAMRussian_ASW.htm

http://www.warships1.com/Weapons/WAMRussian_Mines.htm

http://www.warships1.com/Weapons/WAMBR_ASW.htm

http://www.warships1.com/Weapons/WAMBR_Mines.htm

http://www.warships1.com/Weapons/WAMGER_ASW.htm

http://www.warships1.com/Weapons/WAMGER_Mines.htm

http://www.warships1.com/Weapons/WAMJAP_ASW.htm

http://www.warships1.com/Weapons/WAMJAP_Mines.htm

http://www.njahof.org/jager/ship_articles.html

http://mscmga.ms.ic.ac.uk/jeb/or/intro.html

http://www.gwpda.org/naval/br1669.htm

http://uboat.net/boats/u427.htm

http://www.forces.gc.ca/site/fourth_...03/06_fd_e.htm

______________________________
.

.
The Ancient History of the Submarine
"Subgenesis"

Manual TDC
"HTDC Tutorial"
.

3. Sounds like in SHII they modelled the radius on a simple, half the distance, half the power or something similer. When really the power of the charge in water decreases greatly with distance.

Which was why the bouncing bombs used for Dams had to have back spin applied so that they'd hug the wall as they went down.

Hpefully the devs will take heed of your excellent information.

4. <BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by radsov:

Sounds like in SHII they modelled the radius on a simple, half the distance, half the power or something similer. When really the power of the charge in water decreases greatly with distance.

Which was why the bouncing bombs used for Dams had to have back spin applied so that they'd hug the wall as they went down.

Hpefully the devs will take heed of your excellent information.<HR></BLOCKQUOTE>

Hi.....

I am not sure how they modelated the expansive wave, but the distance at wich the depth charge can make a lethal damage with a lethal flooding is so exagerate........

Real values was very lowest than SH2 values......

I use CB's DEV 5 V3 mod, this mod give to the DDs a very random behavior, they are not more linked with a rope to your periscope......

They still dangerous if you have your periscope out of the sea surface...... but when submerged, they has not a magic hability to find you any more.......

When they locate you, many times they loss the contact, or droop the depth charges not exactly over you, instead they launch the depth charges befor you, after you, at one side or another........

Adding my mod of historical lethal radius to CB's Mod, DDs need to put the depth charges into the real and historical lethal radius to cause severe damage to you..........

No more "laser guided depth charges"

The result is very interesting, the DDs need to much more time to kill you.........

You have now the hability to scape from them, if you can not to reach a safe distance and scape from DD's detection radius, they still attacking you up to they sink you, but it takes many hours, 10, 20 and may be 30 hours to sinks you...... step by step with small damage each time............

But, some times, they have very good luck, and they hit you in the first attempts, and if they put a depth charge on you into the lethal radius................

You are done.......... in the first or second attack........... but his not happens always.

Much more realistic, and adrenalinic, you must to take antiacid for your stomach.........and more in concordance with survivors stories.......

http://uboat.net/boats/u427.htm

http://www.forces.gc.ca/site/fourth_...03/06_fd_e.htm

Will be so great to have this kind of very random DD's behavior, and non magical depth charge release, and real and historical lethal radius in the depth charges.........

Thaks for your comments..........regards, Red.

______________________________
.

.
The Ancient History of the Submarine
"Subgenesis"

Manual TDC
"HTDC Tutorial"
.

5. Thanks for those links.

Modelling the lethal radius isn't that hard. One equation that is simple but realistic is the one used for light intensity where the energy reaching any given point is the inverse square of the distance from the origin.

So if you have a explosion that can generate 400kg/square cm at 1 metre, then at two metres distance the explosive pressure has dropped 4 times to just 100kg/square cm. A dramatic drop in just 1m. At 3 meters this would drop to under 50kg pressure.

In the water and with the shape of the charge used there are other factors but the above would be close enough to reality to be OK. Unless anyone here knows different ? I'm no maths expert at all This just seems like it would work well to me.

I hope they do model the explosions in water on pressure to the hull and calculate this against the hull resistance.

6. Thanks, Radsov......

You are right, but it do not depend on us, almost in SH2 it is not into the open codes......

I am not sure how expansive wave is modelated in SH2, but I had noted damage is reduce by distance increase, but it is not posible to calculate or know if this reduction is lineal or cuadratic...........

The main problem is the lethal radius at wich the depth charge can perforate your hull and produce a terminal flooding is so exagerate, in some cases 10 times biger than in the real life, plus the hull resistance was based on the sub tonnage instead on its hull resistance to depth pressure.......plus the damage value was so exagerate too..........

Imagine, a 280mm shell has asignated a damage value of 15, and it has about 250kg
of explosives and runs at more than 2 times the sound speed...........

A 380mm gun shell has asignated a damge value of 42 with a weight of 800kg, flying at
more than 2 times the sound speed, and with about 650/700kg of high explosives.

A 406 mm gun shel as a damge value of 51, with about 800/900 kg of high explosive,
and a weight of more than 1030kg at more than 2 times the sound speed.........

And a depth Charge of 250lbs. with 78 kg of TNT explosives and near to "cero speed" as
a damage value of 35 !!!

There was no technical method to stablish a correct value for damage level into the game.

Then I decide to check another weapons to make a comparison.........

In example the bombs in the game....

Considering a explosive filling rate of about 60%

I found damage value for bombs was.....between 0.08 and 0.17 damage points for each kg.
of explosives............

Bomb average value was 0.13 damage points for each kg. of explosives..........

Looking into the cannon shell damage values, we found.........

A gun shell of 280mm, and 300kg has 0.06 damage points for each kg. of explosives.

A gun shell of 380mm, and 800kg has 0.057 damage points for each kg. of explosives.

A gun shell of 406mm, and 1030kg has 0.6 damage points for each kg. of explosives.

We can consider an average of 0.06 for gun shells...........

We must to consider, gun shells has a lot of kinetic energy accumulated at impact moment,
they fly at more than 2 times the sound speed.........they must to have lot of damage level,
with no explosive explosion, only with their kinetic energy.

If we consider the kinetic energy included into the damage level, the damage level
corresponding to the explosve explosion, will be so smaller than registered above........

For to not favor too much the submarine, I consider its damage level is corresponding
only for its explosive, without considering its kinetic energy.

This values make the sim, very well playable, but there was a problem with Type II
and Type VII.

Due to the low tonnage of Type II and Type VII, they do not reach the dramatism level
of the Type IX and Type XXI.....

Type II and Type VII remains very vulnerable to depth charges, because the game stablish
damage based on ship tonnage, due to this, I decide to increase all Type II and Type VII
submerged tonnage.

Here the problem........ how to stablish a hull integrity and degradation acording to
real or similar to real values.

Discusing in the Subsim forum, Rommel make the sugestion to use the crush depth or
maximun operational depth to stablish a real diference between diferent submarine
type hulls......

Looking into the estimated crush depth, values found in the web are so diferent......

Somewhere, in a web page, information saids, a Type VII C/42 as a maximun operational depth
of about 200m and a crush depth of about 400m.
And a Type XXI, as an operational depth of about 250m and a crush depth of about 500m.

As we can see this values are so diferent than the game values..........

As the crush depth is an estimated value, I decide to take the maximun operational depth,
it is suposed, this value is directly related to ship crush depth and maintain a same ratio
between diferent sub types.

Based on maximun operational depth, I take the Type XXI in the game, and let it as it was,
with the same tonnage, and start up changing others subs tonnage to stablish the same ratio,
between subs tonnage, than between subs maximun operational depths.........

With this change, we ensure the hull resitance will have the same ratio between diferent
subs types, as beween the maximun operational depth beween diferent subs types.

Changes on submerged tonnage do not affect the game, even if you sunk a sub, the tonnage wich appears is the surfaced tonnage not the submerged one........

a trick but works fine......

Will be good to not have this same problems or unreal behavior in SH3

Thanks for interesting in this fact, it is very important for game realism and inmersion, and not too much considered.......

Regards, Redwine.

______________________________
.

.
The Ancient History of the Submarine
"Subgenesis"

Manual TDC
"HTDC Tutorial"
.

7. How did you determine the lethal radius of the various depth charges Redwine ?

8. Hi..........

I put the historical declared value into the corrsponding program files as you can see in the mod......

Declared values was into the web pages linked above........

in example :

http://www.warships1.com/Weapons/WAMBR_ASW.htm

They was the distance at wich the depth charge can perforate with a lethal flood level a determined tick hull, an average subhull of the age of making of the depth charge........ may be the same depth charge has lower effect on a later war sub.......

For the knowed depth charges values I used the historical declared in technical builder info............

For the rest I those I had not info, I use a proportional value based on its explosive quantity.......... mainataining the same relationship of meter radius by each kg of explosive........

I had obtained info for lethal radius of TNT and for MINOL/AMATOL explosive types......

If the mod is not perfect, almost it is more near to reality now...........

Used in combination of the hull resistance correction, ( based on hull max depth not in ship tonnage, changing submerged tonnage ) and in combination with the Mod of CB.........DES5 V3 .......... you have a new game...........

______________________________
.

.
The Ancient History of the Submarine
"Subgenesis"

Manual TDC
"HTDC Tutorial"
.

9. Sorry I should have worded my question better , I meant how did you determine the lethal radius of the deptch charges in the original SH2 game paremeters. At the begining of the thread you mention finding one charge that has a lethal radius of 50 metres.

10. Into the "System" folder you have the .ADF files wich has the settings as text

______________________________
.

.
The Ancient History of the Submarine
"Subgenesis"

Manual TDC
"HTDC Tutorial"
.

#### Posting Permissions

• You may not post new threads
• You may not post replies
• You may not post attachments
• You may not edit your posts
•