An accurate Depth Charge

hopkins32 · 08-22-05, 03:06 PM

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 · 08-22-05, 03:55 PM

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 · 08-22-05, 05:09 PM

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? · 08-22-05, 05:24 PM

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

hopkins32 · 08-22-05, 05:36 PM

this is the link to the info on it

http://www.de220.com/Armament/Depth%...pthCharges.htm

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

hopkins32 · 08-22-05, 05:42 PM

Quote:

Originally Posted by 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?

all the way to the bottom

but seriously im not sure but i know its much deeper than your sub can go

Pablo · 08-22-05, 06:30 PM

Hi!

U-boat.net 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 · 08-22-05, 06:39 PM

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 · 08-22-05, 06:42 PM

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 · 08-22-05, 09:42 PM

Hi!

There's some more information on depth charge damage from this site 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 · 08-22-05, 10:28 PM

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)

Jungman · 08-22-05, 11:08 PM

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....
---------------------
Look at my pic, I am Kaptain Kangeroo! LOL

Average Joe · 08-23-05, 02:03 AM

Quote:

Originally Posted by Jungman

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.

Catfish · 08-23-05, 02:52 AM

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. ..."

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 · 08-23-05, 06:34 AM

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. 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. 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

08-22-05, 03:06 PM	#1
hopkins32 Mate Join Date: Jul 2005 Posts: 55 Downloads: 0 Uploads: 0	An accurate Depth Charge 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 ..... __________________ _________________________________ The Ocean Floor is littered With Careless Captains.

08-22-05, 03:55 PM	#2
CCIP Navy Seal Join Date: Apr 2005 Location: Waterloo, Canada Posts: 8,700 Downloads: 29 Uploads: 2	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. __________________ There are only forty people in the world and five of them are hamburgers. -Don Van Vliet (aka Captain Beefheart)

08-22-05, 05:24 PM	#4
What A? A-ganger Join Date: Aug 2005 Location: Sweden Posts: 74 Downloads: 0 Uploads: 0	Question: Is there any "safe" depth? Most of the subs can make it down to 200meters but how deep can a DC go? __________________ Always check your radar.

08-22-05, 06:39 PM	#8
FUBAR295 Krusty Krab Join Date: Mar 2002 Location: Decks awash in the North Atlantic Posts: 1,450 Downloads: 493 Uploads: 0	By chance, does anyone know what the sink rates SH3 uses for it's DC's or where to find them. Good Hunting, FUBAR __________________ Good judgment comes from experience. Unfortunately, the experience usually comes from bad judgment.

08-22-05, 10:28 PM	#11
hopkins32 Mate Join Date: Jul 2005 Posts: 55 Downloads: 0 Uploads: 0	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) __________________ _________________________________ The Ocean Floor is littered With Careless Captains.

08-22-05, 05:09 PM	#3
HW3 Navy Seal Join Date: Apr 2005 Location: Gresham Oregon Posts: 6,576 Downloads: 458 Uploads: 0	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.

08-22-05, 05:36 PM	#5
hopkins32 Mate Join Date: Jul 2005 Posts: 55 Downloads: 0 Uploads: 0	this is the link to the info on it http://www.de220.com/Armament/Depth%...pthCharges.htm HW3 I think that would be rather hard to do unless the game is already making the the necessary adjustments .

08-22-05, 06:30 PM	#7
Pablo Commodore Join Date: Apr 2005 Posts: 641 Downloads: 168 Uploads: 0	Hi! U-boat.net 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

08-22-05, 06:42 PM	#9
Catfish Dipped Squirrel Operative Join Date: Sep 2001 Location: ..where the ocean meets the sky Posts: 17,776 Downloads: 38 Uploads: 0	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

08-22-05, 09:42 PM	#10
Pablo Commodore Join Date: Apr 2005 Posts: 641 Downloads: 168 Uploads: 0	Hi! There's some more information on depth charge damage from this site 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

08-23-05, 02:52 AM	#14
Catfish Dipped Squirrel Operative Join Date: Sep 2001 Location: ..where the ocean meets the sky Posts: 17,776 Downloads: 38 Uploads: 0	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. ..." 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

08-23-05, 06:34 AM	#15
Pablo Commodore Join Date: Apr 2005 Posts: 641 Downloads: 168 Uploads: 0	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. 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. 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