Depth Charge Lethality Poll

[tater]

Hard data about this is very hard to com by. All the various navies seemed to think that a 300lb DC would be lethal within an average of about 6 meters. They don't list the depth, however.

That means a single DC within that range will kill a sub, or force it to the surface.

Current DCs are no where near that effective. Not even close at 6m. You can have them go off in contact, or actually inside the sub and it won't kill the boat for sure. I did a lot of testing on this, and single DC kills are virtually impossible.

So, the questions...

First, in the case of depth charges detonating close enough that the explosion graphic overlaps the hull (2-3m), should a single DC on an undamage sub be:

1. Certainly fatal.
2. Almost Certainly fatal (75%+).
3. Probably fatal (51%+).
4. Possibly fatal (10-50%).
5. Rarely fatal (<10%).
6. Never fatal.

Second, in the case of the 6m radius mentioned, should a single DC on an undamaged sub be:

A. Certainly fatal.
B. Almost Certainly fatal.
C. Probably fatal.
D. Possibly fatal.
E. Rarely fatal.
F. Never fatal.

FATAL means the either an instant spinning death screen, damage that REQUIRES blowing tanks to surface, or a mission kill (no more engines, props, fuel, etc).


My personal answers would be: 2 and D, given no good source to prove it otherwise. I tend to think it might more realistically be 1 and C, however. The current game (stock) is 4 and F, as a comparison (with any mod that doesn't up DC EF values or radii—so stock, rfb, and TM are here).

tater

[Reaves]

I'd say 3 and D but 2 and D would be better then stock.


I wouldn't want the game to be too hard if you know what I mean.

[tater]

Well, when I finally dial stuff in, I might make a couple versions available. An overall mod to the dat/sim/eqp files for the ships that all use, and a couple versions of the zon with different EF values etc. Just curious what people think so I know how to dial 'em in.

I should add the caveat that single DCs WILL kill you right now if they are in virtual contact (inside MinRadius) and the boat is DEEP. Then it will domino since the boat will instantly be below crush depth. For this I am assuming only moderate depth, perhaps 40-50m (IJN claimed a single 250kg GP bomb turned DC would kill a sub---about equal to their 162kg warhead type 2, maybe less cause bombs have more jacket, less explosive than DCs).

[CCIP]

Personally, what I really miss a lot of times is a chance to die slowly. I've no objection to direct or near-direct hits being very deadly, but I'd prefer it'd end with my boat flooding uncontrollably while I try to blow ballast and lose the battle than just having the control taken away instantly and the boat plunging down. :hmm:

At distance, I'd like minor compartmental damage to be a bit more frequent.

[Reaves]

Originally Posted by CCIP

Personally, what I really miss a lot of times is a chance to die slowly. I've no objection to direct or near-direct hits being very deadly, but I'd prefer it'd end with my boat flooding uncontrollably while I try to blow ballast and lose the battle than just having the control taken away instantly and the boat plunging down. :hmm:

At distance, I'd like minor compartmental damage to be a bit more frequent.

I agree with this. In older sub games (i'm thinking it might have been SH2) I remember receiving major flooding in my bow compartments which caused my sub to slowly sink. Luckily I was in shallow enough water to hit the bottom and be able to slowly repair. I haven't had this happen in SH4 although that could just be the luck of the draw.

Either way, i'll never forget that moment. I thought I was done for but someone was looking out for me.

[tater]

This poll is for "shacks." Direct hits inside what was considered lethal (6m) and in virtual contact (well within the game's MinRadius value).

The distant damage is then semi-easy to tweak with MaxRadius.

Right now there is no such thing as a single hit kill on a sub. Just doesn't happen at moderate depth (it will if you are near crush depth).

Large MaxRadius values make a single hit do damage to more compartments, which increases "contact" lethality, but not enough. If the EFs are upped a lot, and the radius is still huge, they become too deadly presumably.

Oddly, I made some DCs with the MinEF at 499 and the MaxEF at 500, and still didn't get 1 hit kills.

tater

[tater]

1st post edited:

FATAL means the either an instant spinning death screen, damage that REQUIRES blowing tanks to surface, or a mission kill (no more engines, props, fuel, etc).

Again, this is only for "skin kills" where the bomb detonates in virtual contact for part 1, and the presumed lethal radius for part 2.


tater

Originally Posted by CCIP

Personally, what I really miss a lot of times is a chance to die slowly. I've no objection to direct or near-direct hits being very deadly, but I'd prefer it'd end with my boat flooding uncontrollably while I try to blow ballast and lose the battle than just having the control taken away instantly and the boat plunging down. :hmm:

At distance, I'd like minor compartmental damage to be a bit more frequent.

I also have to agree with CCIP. The instant death screen sucks bad. I modded the U-boat armor levels in SH3 for my latest mod to where the U-boat will not be instantly destroyed followed by a death screen. Now, the U-boat will only be destroyed by hull integrity reaching zero from being dragged down by flooding and being crushed or being blown to pieces on the surface. An instant death screen from one close depth charge may be the most realistic, but it sure as hell isn't fun for a game.

But I agree with Tater. One or two very close depth charges should be enough to kill a sub. Just not instantly.

[Ducimus]

RE : instant death

I think the cause in this might be.. i suspect, some of the fundamental mechanics have changed in code.

For instance "crash speed". It used to function as a variable about how fast, or slow your sub bleed hitpoints when below crush depth. Set it for real low number, you sub crushed real slow, and you had time to recover.

It does not do this in Sh4. The game seems to making an arbitrary decision that once you've been blow crush depth for X amount of time - game over, period. Going below crush depth, i did not see any H.I loss at all. just 0% damage and then BAM 100%, with nothing in between.

Maybe the speed is still too high and i need to slow it down more? but i doubt that will solve anything except to delay the abitrary decision the game makes.

[Peto]

2,D

[tater]

I think it's important to add that the ability for a single DC to kill a sub becomes a little more important when the escorts have realistic numbers of charges. If you only need to avoid 18 early war, instead of 80, they need to have a more realistic effect. Of course we then get into the problem of not being able to out dive the DCs, or the limited settings available for the DCs (30/60/90m).

So I would tend to err on slightly less lethal.

Watching a zillion DC attacks with external cam on, I was stunned at how many DCs it took to kill me where they were touching or even inside the sub. Any of the possibly fatal settings would mean at the very least pretty severe damage, which is also fine I guess.

tater

[Ostfriese]

Doesn't the effect of a DC depend on the actual depths as well? Wasn't it: The deeper the sub the lesser the damage range of a DC?

[tater]

I don't think the game takes depth into account at all. In fact, since DCs can do hitpoint damage, which makes your crush depth more shallow, the deeper you are when hit, the more dangerous it is for you.

Cool pic I found:



A quote from a ww2 USN manual:

The effective radius of the percussive wave depends upon the structural strength of the attacked vessel, and no definite values can be stated. Approximate information indicates that a 600-pound charge may cause moderate damage at 80 feet, but to be fatal it must explode within about 30 feet. The 300-pound charge may prove fatal within 20 feet. It is to be noted that doubling the weight of charge does not double the effective radius.

May prove fatal at ~6m for what would be the biggest IJN DC (162kg warhead). That maps to D I guess. 2 or 3 and D...

tater

[Peto]

Let me know if I can help you with any testing.

[swdw]

Originally Posted by tater

I don't think the game takes depth into account at all. In fact, since DCs can do hitpoint damage, which makes your crush depth more shallow, the deeper you are when hit, the more dangerous it is for you.

Cool pic I found:



A quote from a ww2 USN manual:

May prove fatal at ~6m for what would be the biggest IJN DC (162kg warhead). That maps to D I guess. 2 or 3 and D...

tater

Ok, first you are right about depth being a factor. But pondering on this I started to wonder if it doesn't have as big an effect effect on cumulative damage you take as how easy it is to exceed a catastrphic stress. I.e. less than catastrophic and the hull rebounds, but because of the increased depth and stress on the hull, the added pressure and uneven application of pressure makes it easier to exceed a catastrophic point. So if it's not catastrophic, you don't take significantly more damage, only a smaller percentage more, but you exceed the catqstrophic failure point easier. Wish I could find a good paper on this.

The reason doublig the charge doesn't double the range is because of the way the shock wave dissipates.

Here's an example I was able to dig up talking about a shock wave in air:
http://www.makeitlouder.com/document...stimation.html

In water, there is more force dissipated faster because of the density of the fluid.

So for grins lets say a 300 lb and 600 lb DC have 100% effectiveness at 1m and we'll use a loss factor of 0.5 for every 2 meters past that. (These are merely for illustration, not actual numbers and rounded of to the nearest 0.X)

So here is the theoretical dropoff of 0.5 for our example:
distance . . . 300lb . . . 600lb
3m . . . . . . . 150 . . . . .300
5m . . . . . . . 75 . . . . . 150
7m . . . . . . . 37.5 . . . . . 75
9m . . . . . . . 18.8 . . . . . .37.5
11 . . . . . . . 9.4 . . . . . . 18.8
13 . . . . . . . 4.7 . . . . . . .9.4
15 . . . . . . . .2.4 . . . . . . .4.7
17 . . . . . . . 1.2 . . . . . . .2.4
19 . . . . . . . 0.6 . . . . . . .1.2
21 . . . . . . . 0.3 . . . . . . .0.6

So even though you start of with a charge twice as powerful it only takes a distance 10% greater, not twice as great for the force to drop below 1 lb

This is an extremely simplified example because I'm leaving out possible log or natural log functions which would make the drop off faster past a certian point, and I'll guarantee the factors are off. But this shows why doubling a charge does not make the DC capable of creating the same damage at twice the distance of a DC half it's size.