Depth Charge Lethality Poll

[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.

[Ducimus]

Tater, just FYI, your depth charge settings could concievably change if you use some of the changes ive done to the submarines zon files ive been yapping about since last night.

[tater]

I'm sure they will, lol.

I assume that in game the damage falls of linearly with distance between MinRadius and MaxRadius.

You dropped the armor, but not the ALF, right? So 20*4=80. 80 is now the damage cutoff.

So if a charge can do 230 points at 4.5, it will do 115 at 9.5m, it'll do 80 at 11m. Outside 11m it does nothing at all.

tater

[panthercules]

I love what you're doing to try to make the D/C experience more realistic, BUT, I hate to say it but this is a pretty meaningless poll/question the way it is posed in a relative vacuum.

If (and this is an assumption I acknowledge is true for me but not necessarily true for everybody) the "best" realism is one which achieves a realistic end result - in this case a realistic chance of escaping with damage vs being destroyed - then you can't really answer this question about what an essentially direct hit would do to your sub unless you can also answer/address the question of whether the percentage chance of these direct hits is reasonably accurate/realistic in the game. Obviously, if it is, then you would want the results of those direct hits to also be reasonably accurate/realistic. BUT, if for some reason the AI escorts typically get a much higher percentage of such direct hits than would be historically accurate, then for sure you would not want to make the effects of such direct hits be too lethal (even if they would be IRL) because then you would have distorted the lethality outcome too much to the deadly side.

From the comment below ("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.", it's hard to tell for sure what was happening on a percentage basis, but it sounds like maybe there were a large number of direct hits. If there weren't all that many US subs lost due to D/C attacks, and the game is throwing off a lot of direct hits, then it doesn't sound like a good idea to make direct hits too lethal unless you can also reduce the number of direct hits experienced.

The best result would seem to be some way to increase the number of minor (but significant) damage results, such that D/Cs would be something to fear and could cumulate to deadly damage, but where the player would still have a reasonable chance to at least try to deal with the damage most of the time. After all, if you're not playing with external views on while you're being attacked, then you really don't know or care how close the D/Cs really are (i.e., whether they're 20 feet or 30 feet away) - all you really know is are they close enough to be damaging you or not.

Of course, that assumes that the damage control model in SH4 works or can be made to work like it eventually did in SH3 with LRT. So far, I haven't encountered the right circumstances to test the damage control system meaningfully, so I don't kow whether it works or not, but I hope so - otherwise, you might as well go for the instant screen of death with super lethal D/Cs and spare us the disappointment of dealing with a damage control feature that doesn't work.

[tater]

Excellent points.

One thing, my changes to the DCs also includes accurate loads of DCs on the escorts. So some might carry 18 DCs instead of what they now carry (80).

Also, I should be clear. I was trying to get shacked. My test case was a single DC exploding so that the explosion graphic touched my sub. I made an Elite Minekaze with 1 roll rack and used TM sensors, and loaded up the Minekaze like bungo pete with sensors on top of that. If a DC exploded nearby, but didn't touch I quit the mission and started over.

Even then, had I been trying to evade, and/or deeper than 100 feet, he'd not have hit me often in all those tests.

Really, the point of the poll is to find out how many folks think that it should be possible for a single DC to take out a sub. I agree that if they are shacking you all the time, then they need to be toned down to have historical outcomes. I would assume, however, that the sub goes deep and tries HARD not to get hit as a baseline as well (I'm sure skippers treated a DCing as the life or death situation it was).

I might also be inclined to make single DC kills unlikely for the type 95s since in RL they only had 2 or 3 depth settings, and the deepest was 60m for most of their lifetime in service.

tater

[panthercules]

Understood - I certainly think it should be possible for one DC to kill the sub, though hopefully not that likely, and it'd be nice if it weren't the immediate sceen of death, but where you'd have at least a minute or two maybe to try to blow tanks and make it to the surface, or maybe hit bottom if you're shallow enough and send the survivors out through the escape hatches with the breathing gear