I noticed something very wrong with AI depth charge drops
 

I was testing my new RND and decided to see if my theory that the fall of the DCes is directed at player’s U-Boat no matter what the angle of approach from the attacking escort.
I found a perfect example so allowed myself to not take evasive action to see if I was correct.
The DE was off my port bow as I made 3knots at 220 meters. It crossed my bow at zero and was at a constant distance. It then was reported closing at 17, closing at 30, closing at 77 and closing at 100 degrees at which I heard the sounds of DC splashes. It then was moving away at 200. Now if you can picture a drop over me 220 meters nearly 700 feet above me and I am moving at 3 knots.
At 3 meters per second it should take 70 seconds for the DC to reach me. If it is dropped on my position I would have moved more than 350 meters in 70 seconds. That is four lengths of my boat. Since the drop occurred while the escort was going from 100 to 200 degrees relative to my direction that would mean he was dropping slightly behind my center. Even if the DCes fell straight down with no momentum from the moving escort I would not be where they fell. I would have had to have been completely stopped and they would have had to drop straight off the escort to hit me behind the conning tower.
Yet, they landed directly on top of me.
That can mean, assuming I am not mistaken and it would be wrong to assume that but still possible the DCes are dropped with knowledge by the game to where it knows I will be and defies the change in position almost like if it drops where you are it hits you. That can’t be right and I have tried to access this but the fact is my position and direction relative to the escorts's position and direction are correct. They are known facts (to me) that made this an easy to analyze situation
That means that every time you hear a drop it will hit you at the correct depth (on escorts of 2-3-4 rated crews at least) even if you are moving in a different direction for the path of the cans.
The only way that will not happen is if you alter course each time irregardless of what your position is relative to the drop. That makes it hard to figure as practical solutions can be worse than turning toward the should be explosion area.
Since I did that last night for 51/2 hours changing course with every drop it can work but that is not only not real, historically, but not fair for a game, not sporting mates! (The relaity is more the concern, though!)
One of the things real U-Boats did was actually stand still. More times than not they withstood all day long DC attacks and lived to tell the story.
Why can't we?
I don't want stupid AI either. But somewhere in between is there a possible solution to this?

How can we change that?
I am unfamiliar with how Depth Charges work and what it would take to modify them and even if we can modify the drop rate and explosive results can we modify the way they can be dropped with deadly precision?

Can someone speak up on what we can do and how DC are configured and what options we have for modifying them? Correcting this would be a big leap forward in hisorical reenactment!

Wulfmann

I have noticed that an escort with a K or Y gun will actually attack you in such a way as to 'aim' the K or Y gun at you. Something that it does quite effectively.

How close the hydrophone/sonar can hear you, often right up to when it is on top of you assists the pin point drops.

Where the escorts drop the depth charges cannot be moded, there is no setting regarding the precision on the location as there is on the depth.

A Depth Precision=20 means if it has your depth at 100 metres then the depth charges will explode anywhere between 80 and 120.

So I would be confident in saying that you were hit with a depth charge from the escorts K or Y gun.

you need to tweak the sensors so they lose touch w/ you at close ranges -- as in real life. then the escort drops its dc's at the last predicted location. so, if you continue straight, level, at a set speed, you'll get hit. if you alter course (while the escort can't pick you up -- ie at silent running and below their asdic beam) you can get some distance between the explosion area and your boat.

of course, the settings to get that magic sweet spot between uber detection and blind escorts are not precisely nailed down as yet -- many, many variables.

This was a bit different and while both gave some good info I repeat.
This drop occurred on top of me and I had to move a considerable distance so there is no way regarding the laws of physics that a DC would end up exploding right on top of my first quad 20MM as I saw it come straight down and explode as I watched in my peri looking aft.
The K-gun would have had to throw that 300 meters and it would have had to drop at an incredibly coincidental rate to do what happened.
It was because the movement of the River DE was easy to identify I stayed on slow speed and not change course so I could see if what I have long suspected occurred.
I have been getting drops on my position from angles that are just not realistic. It would only happen in real life if a computer could track the U-Boat and throw the cans to the spot figuring the drop rate and angle precisely. That was impossible in 1944.
If it happened once in a while that would be one thing. But, this happens with virtually every drop. If I maintain a constant course I will be dead in a couple minutes while in real life U-Boats went deep and it was so difficult to accurately ascertain their location and depth they often just sat there and waited for the enemy to run out of cans.
The last thing I want is an easy sim. But, it was tough enough in real life without having forget and fire depth charges.
I will look at those files and see what altering the numbers do. What have you tried and what results do you think mimic reality better?

Wulfmann

3kts = 350 meters in 70 seconds ?
Isn't that closer to 10 kts than 3 ?

that's exatly the point -- the ai makes an incredibly accurate drop based on your known speed, heading, and depth. perhaps that's not realistic (more later) but that's how it works -- if you don't alter one of those three variables, you'll get cans landing on your head. the point of altering the sensors is to give you some "dead time" out of the "field of view" of the ai sensors to allow you to make changes in course/speed/depth without those changes instantly being picked up (which is the non-realistic bit).

as a historical aside re fire control -- the rn introduced the type 144 asdic in late 42 -- the projector/receiver was the same as the type 128 set, but it was connected to an analog fire control computer that allowed calculation of precise drop times. later systems were connected to weapons directly, e.g. squid dc mortars -- the entire aiming and firing process was automated. nevertheless, that stuff shouldn't really be happening 'till late wr.

Might be 350 feet in 70 seconds,LOL
Lets see. 3 KTs is 18,000 feet in 1 hour
So divide that by 60 (minutes) and you get 300 feet.
that would be 5 feet per second so it would be 350 feet not meters.
So the straight drop over me drifted 350 feet to land on top of me at a 90 degree angle from its directional path. Not as bad but just as wrong!
Wulfmann

Yeah Im thinking only about 1/3 of that max could be attributed to the K-Gun

Wulfmann,
350 feet = 106.68 metres and the max range for a K gun is 120 metres.

TB, that does not change the fact it happens so often contrary to what I read and that is more the point, even if you are correct in this instance.
Not only that I get way too much damage. That hit I witnessed. It exploded about 5 feet above the quad 20MM mount. It sank the boat with that hit and I have read countless accounts of such close cans causing damage but not near what I get.
As I asked on the other good thread the two files in the configuration folder, Sim and sensors. Which one is for player's boat and which is for the AI. I really want this to be as hard as it was for the real boats but not harder. It was hard enough without making it worse. I certainly do not want it any easier either. That would make it no fun to me.

Good accounts though, well appreciated responses.

Wulfmann

120 meters is impressive... nice to have specifics too, thanks.

This was actually fixed months ago.

Go here: http://u-boot.realsimulation.com/

Look for RealDC_2.zip. If I remember rightly it also contains a modified Sonar file which limits how close they can hear you. If not, I'll look through my files when I get home.

Just a few things to think about:

If the can really exploded some 5ft (that's less than 2 meters!) above the 20mm, it exploded proably less than 5 meters above the hull. There's a really big chance the DC would have ruptured the pressure hull at that distance when the DC had a blast radius of 10 meters. And in 200 meters depth ANY rupture in the pressure hull combined with the immense water pressure around the boat would crushed the boat to pulp instantly. After all you alreay were near crush depth of the boat! At 20 meters that's a different story.

In addition: where do you get the information on those counteless accounts? How would a sub crew have any indication of how close the cans explode? They didn't have an external camera and a free view mode. And at 200meters it's pitch black and a flashlight won't carry 2 meters, so seeing a DC fall through the scope is impossible. They probably examined the damage to the outer hull and thought: "My, this can must've been close"!

The problem with the accuracy can be quite unnerving, but with evasive maneuvers (not only lieft and right, but up and down as well) you have a pretty good chance of getting rid of them. And although the DC is a highly inaccurate weapon several DD commanders simply had a lot of experience and a gut feeling on when to drop them without the help of a computer. Otherwise Germany wouldn't have lost so many boats.

The Destroyers' AI have different ratings. Some are Elite, some are Veteran and some are Green (there are others, I think, but I don't know what they are). Yes, they seem to be a little too accurate. As I said, there is a mod that reduces the blast radius (which is also far too great) and the sonar capabilities, so they lose contact before they drop. Try these and I guarantee you will get blasted for hours and still have a chance to escape.

Another real-world problem for the destroyers was that depth-charges came with precise settings-50ft, 100ft, 150ft etc., with no allowance for in-between. They also at first had fairly shallow maximum depth settings.

Also, Wulfmann, you say that evading a 5-1/2 hour attack by changing course and speed is not historically accurate. Why not? Then you say one thing real u-boats did was stand still. Except for a couple which confused enemy sonar by lying on a fairly shallow bottom, standing still was one thing they emphatically did NOT do. Where did you read that?

As I said, you can withstand all day long attacks with the 'Real DC' mod.

Most boats were sunk near the surface since most reported their demise. The many books I have read talk about multiple close DCes. In Iron Coffins he speaks of sitting in one place and being DCed for 37 hours. Escorts drop all they have, they leave. More come and one and on. But, they survived.
I can assure you if you park your boat in relatively shallow water in SH3 you will not have the same result ever.
While you are right on some assessments like the estimate of where the cans go off the up and down part I will dispute. I have tried that and as the cans are dropped when I am at 220 meters and I drop to 235 meters they exploded right at my depth. When I go up instead, they explode at that depth. The only time they do not explode very close to me is if I hit flank speed. Then they go off a little behind me.
I read way too often about cans going off in the area but still away from the boats. My SH3 has sniper depth charge men
Boats were sunk by deep depth charging for sure. But, most were sunk near the surface by aircraft or damaged in attacks by surface ships before they could dive deep. Even later that was their best chance of survival. For me the best chance is to stay at 14 meters (DCes go off at 20 meters mim) and reload taking shots until I sink 4 or 5 escorts.

I should have a decent chance to survive if I get deep and no chance if I stay at 14 meters. That is not how SH3 plays and I search for ways to make it more as I read ( I have read many many books on this and getting to the deep was where they had their best chance)
The fact I have a better chance doing something I should have no chance and no chance where I should at least have some is my problem and I still seek a solution.

The reason it is important is I would like to have 12-15 escorts for each later convoy but that would be 110% impossible yet that would also be 50% of what those convoys would have.
We need to change things to achieve a number of convoy escorts that changes this from sinking a couple DEs and having an easy go with big scores that never happened for real.
We should maybe get close once (and half the time get spotted and get no shot at all), take our shots go deep and evade to never shoot again at that convoy.

I believe we can find a away to make the escorts deadly while allowing us to increase their numbers to a semblance of reality but not so we have no chance and therefore no desire to bother.


Wulfmann

SS, I have used the tools and keep reducing those and testing them but still am getting sunk.
No, I did not mean turning and increasing speed was not done, mostly. but, I have read many times where they go very deep and either remain still or move at 1Knot and that the variation of the explosions varied from close to far away. Mine are always on top of me.
I have always used 3 rated crews throughout all warships (with BBSm cruisers and trawlers all 4). I recently redid the RND to all 2 rated escorts but greatly increased the number to 8-12 on 1943 on convoys hoping the 2 rating would be less accurate on snipe drops. I was wrong. I don't really see much difference.

BTW, You never did say in the CFG folder which files were for player and which for AI regarding sim and sensor text files. I would like to try different settings for those

From Iron Coffins page 230 (excerpts)(DD was almost on top of them after they had fired at a convoy, observed three hits but dod not make a confirmed kill for this attack)

"Emergency! Dive to 150
-We braced for impact. U-415 fell away clawing for depth, her screws churning violently.- The spread from above exploded just short of the conning tower. Six times in quick succession the boat was beaten and savagely shaken. - Then a fresh series slammed against the hull, driving the boat further into the depths. The Chief leveled her off seconds before she would have rammed into the sand. This noisy maneuver brought down a new salvo. We heard the canisters splash into the water and as they floated down we had little chance to escape them. A dozen detonations-a shattering roar. Somewhere a valve blew and a fountain of water, thick as an arm, spurted across the aisle. The escorts above us-we heard them with the naked ear-assembled for the kill. A third barrage bracketed our trembling boat. Then the devilish grinding of propellers heralded another spread.
Though the sun sank into the ocean and night covered the attackers, they still hurled their cans and the concussions kept crashing our boat into the sandy bottom and blowing her off again in repetitious sequence. By 0600 the next morning we had taken 18 hours of constant beating--- At noon the attacks had not lessened. The British attackers quite obviously took turns; we heard new escorts arrive and take over the chase with a fresh supply. Evening came and the bombardment continued with savage strength-------------- Midnight came once again. The British had pounded us for over 37 hours, dropping more than 300 charges and were still unwilling to halt the pursuit. At 2:15, however."

On and on. The Tommies left and the boat made it home and I might add this U-415 was an obsolete patched up wreck of a boat without a snorkel when the mission started.

Boats were sunk seep but real boats had a better chance than we do and that is my complaint. We should find a way to have 15-20 escorts in a convoy without a certain death sentence no matter what.

Wulfmann

Funny thing that, different peoples' experiences. I go deep and silent running and I hear depth charges dropping far away. Using the mods I mentioned I haven't been sunk yet. I'm playing in mid-1940 now and I expect that to change later in the war.

We'll see.

I do agree though about lying on the bottom being useless in the game. They seem to find you anyway; or so I've heard.

SS, I no longer play before 1943 because it was too easy early. I am, however, trying to tweak 1943-45 to be only as difficult as it was. Since 1 out of 7 were you chances that seems hard enough!
Making an effective escape deep should still give you a good shot at survival. It doea not.
I found before I increased crew ratings and numbers of escorts pre-1943 was just target shooting.


CFG, please if you know, Sim and sensor files. AI or player????

Wulfmann

Wulfmann,
Prof. Dr. Rohwer once wrote in January 1970 in the "Schaltung Kueste" the official journal of the VdU (Union of the U-boatmen);

"If one were to pencil in with red all the factual mistakes in this book it would look like a bloodbath".

And that is just the point as I see it, this is an excellent personal account of this officer but not a serious research-book to base further work on. This was not meant to be such a book.

I have many u-boat books, could always do with more, however I could not agree more with the above statement from the Uboat.net site.

This is not one of my infamous if your not with me you are against me 'attacks' :rotfl: It is that while it was an exciting read, it is more fiction than non-fiction.

I am aware of that. What I like about this book is the sense one gets of the war from a personal point of view. The people killed that were close to him, (that part is fiction, I don't think so) the dealing with stuff about a Navy career and some of the sense of being in the boat which many more historic accounts sorely lack.
I have the Encyclopedia of U-Boats for general reference although it is in general and not specific. I have had other U-Boat books that I end up getting rid of because they are inaccurate, Gunther Prein sank the carrier Royal Oak, LOL, no I am not kidding; from The U-Boat War!)
The above account I quoted was likely not fiction and his writing is from his perspective and not from official records. It would do us well if we could feel while doing SH3 like he recreates his experiences. IMO.

From what I can tell we need to improve our experiences a considerable amount to be only as inaccurate has Iron Coffins.

Still, no one will relay if the sensors and sim files in the data/cfg folder are they for player or AI which is which????

Wulfmann