DepthCharge radius - effectiveness

[danurve]

I was floating an idea to increase the effectiveness of a Depth charge later in the war, and perhaps logicaly less effective in early war. Since tweeker lets us edit DepthCharge_zon I would like to know more about MinEF / MaxEF. Radius is 20, what is a maximum that won't cause the game to spazz?

Thanx!

[Von Manteuffel]

I don't know whether this is of any help but......

The British Type D , introduced in 1917, claimed a lethal radius of 21 metres (70 feet )and a severe-damage radius ( sufficient to force a U-Boat to the surface ) of 42 metres (140 feet). It's believed that these figures were greatly exagerrated and based on effectiveness against early submarines, whose pressure hulls were not as robust as their WWII counterparts.

The MarkIII variant of the Type D was still in service up to 1940 claimed a much more realistic "kill radius" of 4.3 metres ( 14 feet ) with a severe damage radius of 8.6 metres ( 28 feet ). Initially filled with TNT, it later used an Amatol charge

The MarkVII, introduced from 1940 claimed to split a 22mm hull at 6.1 metres ( 20 feet ) and inflict severe damage sufficient to cripple a sub and/or forvce it to the surface at 12.2 metres ( 40 feet ). The change to a Minol charge from TNT, in 1942 claimed to increase these radii to a "kill" radius of 7.9 metres ( 26 feet ) and a severe damage radius of 15.8 metres ( 52 feet ) - Tis is odd since Minol was a mixture of 80% Amatol and 20% aluminium powder and was regarded as not being as powerful pound for pound as TNT??????

The Mk VII Heavy had a 150 lb ( 68 kg ) weight attached, which increased its rate of descent from 9.9 fps to 16.8 fps. Both had an initial maximum depth of 300feet, (92 metres) which increased later in the War to 500 feet ( 152 metres)

Of course, such figures can only be averages, or estimations, as they cannot take into account the damping effect water pressure and density at depth can have on the force of an explosion.

depth charges caused a spherical, non-directional explosion. The shock-wave was not, however uniform within the rapidly expanding sphere of gas. That introduces another imponderable- 2 charges exploding at the same distance from a target could have markedly varying effects. The proximity of the exploding charge to "weak spots" - e.g. hatches, torpedo tubes, rudder and propellors would also have an effect on the damage caused.

[CapZap1970]

Maybe I am wrong, but AFAIK a depthcharge beyond 150 m. is pretty much harmless due to pressure. It won't let the explotion wave be as intense as it should be at shallower depths. :up:
CapZap

[Sailor Steve]

There was a depth-charge mod two years ago that reduced lethal radius to 8 meters, which is just about right. It makes it possible to be attacked for hours and still survive. It might be incorporated into the supermods; I don't know.

[danurve]

Actually, all this information has been very helpfull in understanding what the radius settings mean, or affect. And appriciated - thanks!
I think to leave the EF settings be for now, trying radius settings of 10-15 for effect on a test save. With 3 DD's on the hunt it sure dosen't take much to let them know where you are.

[Von Manteuffel]

Please let us know how things go. Even if it's too complex to build-in and allow for all the variables, it would be good to be able to have DCs in the game which use the average kill and damage radii.

Not sure how, in-game, you measure the distance of an exploding DC from your boat.

Oh, another thing I forgot to mention earlier. Detonations below a sub had an added effect as the gasses from the explosion naturally moved towards the surface. Apparently even in the milliseconds of a detonation, this added to the effectiveness. The physics of underwater explosions are mind-boggling, involving the shock-wave, a vacuum, a steam-bubble etc. etc.

Best of luck.

[Webster]

Maybe I am wrong, but AFAIK a depthcharge beyond 150 m. is pretty much harmless due to pressure. It won't let the explotion wave be as intense as it should be at shallower depths. :up:
CapZap


actually it is just the oposite, due to increased hull pressures the shock wave from the depth charge is even more lethal at deeper depths. i think you are correct in that the shockwave has a much reduced effective range due to the pressure.

[CapZap1970]

Maybe I am wrong, but AFAIK a depthcharge beyond 150 m. is pretty much harmless due to pressure. It won't let the explotion wave be as intense as it should be at shallower depths. :up:
CapZap


actually it is just the oposite, due to increased hull pressures the shock wave from the depth charge is even more lethal at deeper depths. i think you are correct in that the shockwave has a much reduced effective range due to the pressure.
Thanks for the info, WEBSTER!!! :up:
I didn't think about that!! ;)
CapZap

[Sailor Steve]

Estimates varied a lot on what it would take to sink a submarine, but by war's end they were convinced that the real numbers were about 25 feet (8 meters) to crack a pressure hull and 50 feet to cause damage. Outside of that they were pretty much useless except for harassment purposes.
http://www.navweaps.com/Weapons/WAMBR_ASW.htm

[CapZap1970]

Estimates varied a lot on what it would take to sink a submarine, but by war's end they were convinced that the real numbers were about 25 feet (8 meters) to crack a pressure hull and 50 feet to cause damage. Outside of that they were pretty much useless except for harassment purposes.
http://www.navweaps.com/Weapons/WAMBR_ASW.htm
Then the info I had about it was right!!!! :up:
CapZap

[johnno74]

Maybe I am wrong, but AFAIK a depthcharge beyond 150 m. is pretty much harmless due to pressure. It won't let the explotion wave be as intense as it should be at shallower depths. :up:
CapZap

actually it is just the oposite, due to increased hull pressures the shock wave from the depth charge is even more lethal at deeper depths. i think you are correct in that the shockwave has a much reduced effective range due to the pressure.

Hmm, I read in "A diary of a u-boat commander" that the deeper you were, the closer the depth charge had to be to you to do any damage.

[ichso]

But the deeper you are, the more vulnerable you are to damage too.

[tater]

Looking at the .sims for DCs (SH4, but they haven't been modified since 2004, so I assume they date to SH3), there is a detonation_depth setting. One is set to 25 with a precision of 5, the other 2500 with a precision of 300.

What does that value (the depth) mean?

I tried radically changing them, I saw no effect.

tater

[gimpy117]

There was a depth-charge mod two years ago that reduced lethal radius to 8 meters, which is just about right. It makes it possible to be attacked for hours and still survive. It might be incorporated into the supermods; I don't know.

where might this be found??

[tater]

Dunno about the mod, but it's a trivial fix with S3D. Open the DC zon file, change the max radius from 40m to 8m. Save. (work on a copy, obviously).

Still, no one knows if the detonation depth works?

I tried a few values and cannot see the difference. Sad, because this would be SO useful, at least in the PTO where the japanese set their DCs at either 30m, or 60m until lafter '42 when they added a 90m setting.

tater

[CB..]

i sometimes wonder why the focus is placed so heavily on hull damage in the sims..from my point of view i spent a long time experimenting with reducing the hull damage and swinging the emphasis over to systems damage..working on the principle that

a/if your engines torpedoe tubes batterys etc are destroyed your just as dead gameplay wise and must abandon ship

b/from a gameplay point of view it allows you to make far greater use of the damage screen


c/with hull damage you tend to be as a whole in a fairly black or white situation....your fine untill your dead sort of thing..with no huge problems occuring gameplay wise even with major hull damage..where as the irrepairable loss of your batterys or hydrophones or top tubes etc takes you right out of the hunt...
regardless of hull damage...

i rmeber that i was able to set it up so almost no hull dmage occured at all...but all the internal sytems were as fragile as glass slippers..

i got bombed on the surface once and was left with 100 hull integrity ie no hull damage at all....but every single essentail sytem on board was smashed beyond repair..game over..same end result better gameplay IMO

this is kinda relevant to the question simply because it allows the DC's to have a far more dynamic effect damage wise than simple Hull damage...(altho this does happen as stock of course) it means that a slightly more distant explosion which normaly would have zero effect...might in fact cause some minor damage to an on board sytem simply due to the shock wave shaking some instrument of it's mounting or similar...
it was far more unpredictable..and had that Das Boot effect so sought after
dpn't ask me how i did it i can't remember right now..but it wasn't a huge job...you had to rig the DC's (if i remember correctly) to have an unrealisticaly large damage radius BUT compensated for that by reducing the overall damage to change the empahsis from sheer explosive grunt...to a more general bone shaker shock wave... a direct hit would still sink the boat of course..
it was a simple matter of percpetion as to how you intepreted the damage radius figures..there was some work needed on the sub sytem damage settings also...bit vague on that tho...but i found myself quite frequently re-enacting the famous "stuck on the bottom" das boot repair scenario....some times succesfully sometimes in vain....with the stock hull damage settings and set up....it would have been the death screen on each occasion..this way i got to struggle to see if i could rescue the boat....depends on you point of view of course but i found this to be much more immersive gameplay wise than just getting told i was dead....most times i had to admit to myself i was dead as the sub was beyond repair...but every now and then i was able to repair enough of the boat to limp home...tho no further combat was possible...destroyed torp tubes etc etc..and yet again oft times i didn't actualymake it home even after all that work..as any futher damage inflicted by a passing bomber or DD etc was the final coup de grace....it was really a case of all that tension and struggle and gameplay or the "your dead" screen...
no competition really...it did rely on you being honest with your self tho...perhaps roling a dice to finaly decide wether to continue that career or strike that captain off as dead or captured or missing in action etc..but i could cope with that also as again it's good gameplay (for my point of view any way)

heck just remembered something else..

you know that "saving private ryan" concussion effect you got when on the bridge and the bridge gets shelled..all that distorted vision and echoeing noise??
it is possible to extend the boundaries of the trigger for that effect so it happens if a DC hits the conning tower whilst submerged...
now that is fun and immersive indeed...being in the control room and getting that same effect from a close hit to the conning tower was very atmospheric and really did make and instant response to the critical situation absolutely impossible untill it had faded away..genuine cincusion..spent a while trying to extend that efefct to the entire sub but didn't find the correct method...seemed possible tho...that again would be something that would be directly tied to the DC damage radius and again would occur far more frequently if the DC's had a "shock wave" blast radius instead of a direct explosive effect damage radius..you could set it up so almost no damage occured from a normaly ineffective "close shave" DC explosion BUT you still got that shock wave concusion screen and sound effect..which lets face it would be one heck of an addition to the games immersion

it involves a lot of subtle thinking but you can eventualy get statisticaly realistic DC damage radius settings (tho NOT ON PAPER..the on paper settings will innaccurate .but the IN GAME effective radius for the DC's would be accurate...but you get all the extra fun detailing of the above sort of gameplay stuff....but only if your prepared to "let go" of the need for pure stat based realism....numbers in a file no one but you ( and a few other tweakers) will ever read?? or genuine IN GAME realism...what happens in the game is where it counts don't you say?..)
anyhuw it's worth coming at these thing from the "other end of the tunnel" occasionaly

[tater]

Good points, there are certainly different ways of accomplishing simulation within a certain system. Redwine has been working on such a mod for SH4 where the damage is moved towards the systems rather than the hull. It gets pretty comlex, however, since so many different systems become involved. Ship guns need to be able to damage the sub properly, for example, while still having an effect on enemy shipping (assuming that ever occurs in game).

Really, the goal is simulating outcomes as they relate to player decision making.

My interest in DC mods (for the time being) is with playing with the DCs themselves, because the total sub mod you discuss is a daunting project to undertake. Since I am a SH4 guy, part of my interest is to make more historically accurate DCs for the IJN. The stock SH4 DC (there is only 1 type) is roughly like the Type 2 IJN DC. Early on, they had slower sink rates, smaller warheads, and could only be set to either 30m or 60m depth settings. My thought was that is the detonation depth actually worked, I might be able to make more realistic DCs for the early war.

Course that would make gameplay rather easy in deep water, pull the plug and dive below 60m. OTOH, there are MANY places in the PTO where 60m of water would be a luxury.

tater

[gimpy117]

still, where's this mod!!!

[tater]

Does anyone know if the detonation_depth actually works, and if so, how?

tater

[Sailor Steve]

still, where's this mod!!!
I've looked everywhere, and can't find it anymore. I have it in my stuff, but unfortunately I can't get at it right now. The only thing I can think of is to download Beery's RUB mod. I think it was included in that, and he is so thorough with his readme that it will tell you exactly which files to change, and what to.

Other than that I can only wait until I have my computer set up again, and post it somewhere.

[tater]

Can you simply open a DC file copy with S3D (the zon file) and drop the radius to 8m (or whatever value you want)?

Zip up the s3d DC files and post em, i'll do it for you (can't test though since I dont have sh3). If you let me know what the sh3 path is (like: data/library/filename.zon) i will even jsgme them for ya.

tater

[gimpy117]

thanks