An accurate Depth Charge

[hopkins32]

In my search to make an accurate Depth Charge this is what iv found ......A 300-pound depth charge would destroy the submarine if detonated within 10 yards of the hull, 30 yards away only damaged the hull

Feet
30 yards = 90 feet damaged
10 yards = 30 feet destroy

meters
8 m = about 26 feet destroy
27 m = about 90 feet =damaged

Going by this to simulate it in the game would be devastating . Non the less im going to try and make it just for kicks .....

[CCIP]

And where did you find this? :hmm:

Interestingly enough, there's been a post here a couple of months ago on official reports/tests by Doenitz which indicated that depth charges detonating as little as 6 yards from the hull failed to so much as dent it. And then consider the fact that all U-boats after the Type II had double hulls.

[HW3]

You would also have to take into consideration the depth of the detonation. The deeper you go, the more confined the blast zone would be but, the effect would be more severe in that zone due to the pressure on the hull.

[What A?]

Question: Is there any "safe" depth? Most of the subs can make it down to 200meters but how deep can a DC go?

[hopkins32]

this is the link to the info on it

http://www.de220.com/Armament/Depth%20Charges/DepthCharges.htm

HW3 I think that would be rather hard to do unless the game is already making the the necessary adjustments .

[hopkins32]

Question: Is there any "safe" depth? Most of the subs can make it down to 200meters but how deep can a DC go?


all the way to the bottom :-j but seriously im not sure but i know its much deeper than your sub can go

[Pablo]

Hi!

U-boat.net (http://uboat.net/allies/technical/depth_charges.htm) indicates instantly fatal damage if a depth charge explodes within 10-20 feet (3-7 meters) of a U-boat.

I would guess that the closer the sub is to its crush depth the more likely it is that the depth charge's "water hammer" effect will be enough to cause a fatal hull breach, but I have no idea if this is modeled in the game or not.

Pablo

[FUBAR295]

By chance, does anyone know what the sink rates SH3 uses for it's DC's or where to find them.

Good Hunting,
FUBAR

[Catfish]

Hello,
yes, but it is more likely that a depth charge will destroy sealings and gaskets, not the pressure hull itself. The deeper the charge is, the less its primary detonation expansion (what you called "water hammer") will reach. There is a bad effect of the shock, or better compression wave that will travel through the hull without damaging it, but shear off unelastic things inside like bolts (Diesel foundation/basis) and the sealings of tubes crossing the pressure hull. Getting a leak at, say 600 feet, will make a repair impossible without decreasing the pressure by raising the boat to shallower depths first.
Experiments with the late small type XXIII boats showed that a nearby depth charge would "throw" it away without damaging the pressure hull.

Greetings,
Catfish

[Pablo]

Hi!

There's some more information on depth charge damage from this site (https://www.denix.osd.mil/denix/Public/ES-Programs/Conservation/Panther/panther2.html) on results destructive testing on U-1105 by the U.S. Navy, captured at the end of WWII and expended as a depth charge target in 1949.

A 250-lb. depth charge with improved explosives (HBX-2) was placed 30 feet away while the sub was surfaced. The pressure hull was cracked open, and the sub sank in about 20 seconds.

Pablo

[hopkins32]

Thanks Pablo

I have the setting for the DC just about right now . Soon i should have it ready and can let you guys test it out its not as bad as you might think, im testing it in 1943 .

(Make a Backup) :up:

[Jungman]

By chance, does anyone know what the sink rates SH3 uses for it's DC's or where to find them.



DC is only one. 3 m/s stock in the DepthCharge.sim file.

HedgeHog is only one value, I think 6 or 9 m/s. This is the other ASW weapon used in game. These both can be changed.
DH_X_R.sim something....
---------------------
Look at my pic, I am Kaptain Kangeroo! LOL

[Average Joe]

Look at my pic, I am Kaptain Kangeroo! LOL

That avitar reminds me of...

1965 episode:
"Admiral Jed Clampett." This time out, banker Drysdale purchases a yacht for hillbilly millionaire Jed Clampett. After first overcoming Granny's fear of sharks, the Clampetts head to the dockyards, where Jed mistakes a Navy destroyer for his own vessel.

http://i16.photobucket.com/albums/b18/teehole/jed.jpg

:)

[Catfish]

Hello,
Pablo wrote
" ... A 250-lb. depth charge with improved explosives (HBX-2) was placed 30 feet away while the sub was surfaced. The pressure hull was cracked open, and the sub sank in about 20 seconds. ..."
:o From which date did they use those charges ? 30 feet or roughly 10 metres distance are certainly close ... Since the depth charge "size" does not seem to change over the years in SH3, how should this be modelled ? Maybe a later version of the SH3 commander could adapt to this at a later time, copying other depth charge files to the appropriate folder at certain dates (?).
Greetings,
Catfish

[Pablo]

Hi!

I've been doing some more research on depth charge damage, and found an interesting document at the Federation of American Scientists' site, here (http://www.fas.org/man/dod-101/navy/docs/es310/uw_wpns/uw_wpns.htm). The document is taken from a U.S. Navy Surface Warfare Officer's School class, "ES310, Introduction to Naval Weapons Engineering," dated 1998.

See also an excerpt from The Hydrodynamics of Pumps, Chapter 6: "Bubble Dynamics, Damage, and Noise" found at the California Institute of Technology site, here (http://caltechbook.library.caltech.edu/22/01/chap6.htm). It says pretty much the same thing, except with greater detail on how a close-in depth charge explosion kills a submarine. There's also plenty of math for those who are interested....

It appears that the "kill radius" of a depth charge is related to the size of the steam bubble that forms when the depth charge explodes. If the bubble touches the submarine, it forms an air pocket that adheres to the submarine. This results in an extremely powerful jet of water striking the submarine's hull when the bubble collapses.

The size of the bubble (i.e., kill radius) is determined by the relative pressure of the explosive charge (bigger charge -> bigger bubble) and the ambient water pressure (greater depth -> greater pressure -> smaller bubble).

The damage due to more distant explosions appears related to 1) the overpressure of the initial depth charge explosion and 2) the shock wave caused by the collapse of the resultant bubble (sort of like thunder with a kick). The damage caused by this effect within the "kill radius" is several times greater than that of the water jet, but the damage decreases with distance, resulting in the larger "damage" radius.

Hope this helps

Pablo

[FUBAR295]

[quote]By chance, does anyone know what the sink rates SH3 uses for it's DC's or where to find them.



DC is only one. 3 m/s stock in the DepthCharge.sim file.

HedgeHog is only one value, I think 6 or 9 m/s. This is the other ASW weapon used in game. These both can be changed.
DH_X_R.sim something....
---------------------

Jungman,

Thanks I'll check it out!

Good Hunting,
FUBAR

[What A?]

Thanks all! So if you can't avoid a DC attack go deepest possible and slow down, yes slow down...And after the DC's begins to rain order Ahead flank and turn away, after the first ones explode leaving the destroyer both blind and deaf order silent running and stay on your cours or change.

Btw. Do they have a limit of DC's???

[hopkins32]

Hello,
Pablo wrote
" ... A 250-lb. depth charge with improved explosives (HBX-2) was placed 30 feet away while the sub was surfaced. The pressure hull was cracked open, and the sub sank in about 20 seconds. ..."
:o From which date did they use those charges ? 30 feet or roughly 10 metres distance are certainly close ... Since the depth charge "size" does not seem to change over the years in SH3, how should this be modelled ? Maybe a later version of the SH3 commander could adapt to this at a later time, copying other depth charge files to the appropriate folder at certain dates (?).
Greetings,
Catfish

well for the mod im working on i am going to try and use these settings from 39 to 45 sense there is now was to currently use deferent DC types throughout the war.. the standerd 300 pound is best because it the most common and CD used .

Feet
30 yards = 90 feet damaged
10 yards = 30 feet destroy

meters
8 m = about 26 feet destroy
27 m = about 90 feet =damaged

[bobo]

Thanks all! So if you can't avoid a DC attack go deepest possible and slow down, yes slow down...And after the DC's begins to rain order Ahead flank and turn away, after the first ones explode leaving the destroyer both blind and deaf order silent running and stay on your cours or change.

Btw. Do they have a limit of DC's???

I use the same tactic with pretty good success.

And yes, I'm pretty sure they have a limited amount of DC's but if your fight lasts that long, depending on your location (English waters) chances are reinforcements will arrive before the DC's run out. :o At least thats been my experience.

[What A?]

Reinforcment? Yeah tell me about it...lol
http://tinypic.com/view/?pic=azcrk9
http://tinypic.com/view/?pic=azcutu
They can call on air power to...
http://tinypic.com/view/?pic=azdh85
http://tinypic.com/view/?pic=azdhjs