"The All Knowing" destroyer syndrome

[Bilge_Rat]

couple of points:

1. history: I am in the process of re-reading Blair vol. 1, and there are many examples of subs being held down or attacked by HK groups in the early years.

Johnnie walker's escort group was protecting Gibraltar convoys and accounted for many U-boat kills. They would gang up 3-4 escorts on one contact and just keep hammering until they were certain of a kill. They killed the U-boat Ace Engelbert Endrass that way in december 41.

There are also stories of U-boats being held down for a long time. The U-89 was held down for 31 hours in summer 42, until it managed to escape.

2. the game: you have to remember that the AI has 2 states, he has not detected and ignores you or you are detected, in which case you will be attacked until the escort loses contact for a fixed period of time (default is 15 minutes), after which he will go back on course.

I am not the expert, but there are many factors that will determine if you are detected underwater: skill of the escort (there are 5 from green to elite), your speed, your depth, thermal layer, speed of the escort, sea state. There is also 2 doctrines: aggressive/defensive, although I am not sure what they do, and various AI scripts. If a ship is torpedoed or you are detected by a ship or escort, other escorts near by will come over to hunt you down.

you can see an example of how the AI works here:

http://www.subsim.com/radioroom/showthread.php?t=163304


for the moment, I am sticking with the stock AI, until I can figure out how it works. As Ducimus as already shown, it is very easy to create an AI that will find you and kill you every single time if that is what you wish.

[senjorlossi]

Back to the main topic:


I can confirm that in my (in this direction) unmodded game the destroyers exactly konw ANY move I make (OK, as long as they have contact with me). That has really annoyed me already in SH 3, and now it´s back aganin:

Via outide cam I could see that approaching Destroyers (running high speed on a DC run) would always react to any evasive action I would take, even when it is already almost directly above me. For me, this really messes the gameplay, since I have no chance of doing some sort of "last second" maneuvers. The destroyer will always run directly over my position and drop depth charges there. So evasing is always simply a matter of depth and speed, to move out before the DCs explode.

As far as I know, a real destroyer running in at high speed would, at some point, loose contact due to speed and noise and drop the DCs blind at the spot where the U-boat would be assumed to be. Maybe the Destroyer-Commander would take in count a possible evasive maneuver of the U-boat and drop the DCs somewhat to the left or right. But not always right on top of the boat.

I think there should be some "blindness" added to the destroyers when running flank speed on an attack run.

[U-Bones]

Originally Posted by Bilge_Rat

couple of points:

1. history: I am in the process of re-reading Blair vol. 1, and there are many examples of subs being held down or attacked by HK groups in the early years.

Johnnie walker's escort group was protecting Gibraltar convoys and accounted for many U-boat kills. They would gang up 3-4 escorts on one contact and just keep hammering until they were certain of a kill. They killed the U-boat Ace Engelbert Endrass that way in december 41.

There are also stories of U-boats being held down for a long time. The U-89 was held down for 31 hours in summer 42, until it managed to escape.

2. the game: you have to remember that the AI has 2 states, he has not detected and ignores you or you are detected, in which case you will be attacked until the escort loses contact for a fixed period of time (default is 15 minutes), after which he will go back on course.

I am not the expert, but there are many factors that will determine if you are detected underwater: skill of the escort (there are 5 from green to elite), your speed, your depth, thermal layer, speed of the escort, sea state. There is also 2 doctrines: aggressive/defensive, although I am not sure what they do, and various AI scripts. If a ship is torpedoed or you are detected by a ship or escort, other escorts near by will come over to hunt you down.

you can see an example of how the AI works here:

http://www.subsim.com/radioroom/showthread.php?t=163304


for the moment, I am sticking with the stock AI, until I can figure out how it works. As Ducimus as already shown, it is very easy to create an AI that will find you and kill you every single time if that is what you wish.

Given what we have on hand, I am thinking better behavior may be achieved with a combo of the AI mod combined with a shorter than 15 minute "last contact timer". 15 minutes is an eternity vs more than one DD, they can easily cover a lot of area to reaqquire, while also having one sit still and listen forcing you to be very slow. If DC's were more accurate or damaging, it would almost always be short and not so sweet.

The problem would be finding the sweet spot between giving you a chance vs multiples and being able to easily escape a single DD. Perhaps givening the DDs a smaller prosecution window can be balanced by giving them a better chance to exploit the contact - harder hitting DC's ? But first we need to see aggressive behavior that still allows a REAL chance to escape.

With the current AI mod, the behavior of the DD's is good, as well as the sensor capabilities, but... maybe too good still. It ends up with DDs that are aware but somewhat impotent, as likely to kill you by denying the surface as by DC, as opposed to less certain but much more dangerous.

IMO a happy medium on the AI/sensors would be a better starting point than either stock or the current AI mod. Making them give up in 5 minutes ( or 15 for that matter ) just seems like the wrong way to prevent reacquiring. It should be because they "guess" incorrectly and look in the wrong place long enough for you to get away, ie REALLY part of the AI as opposed to just being more aware.

[Bilge_Rat]

Originally Posted by U-Bones

IMO a happy medium on the AI/sensors would be a better starting point than either stock or the current AI mod. Making them give up in 5 minutes ( or 15 for that matter ) just seems like the wrong way to prevent reacquiring. It should be because they "guess" incorrectly and look in the wrong place long enough for you to get away, ie REALLY part of the AI as opposed to just being more aware.

It will require testing. My thinking is more along the line of increasing slightly the passive sensors of the AI, increasing more strongly the active sonar and increasing the time before contact lost until 30 mins.

This way the ability of an escort to just hear your boat before or after an attack is not omniscient, but if they find you, they will look for you for a longer time and be able to hold contact better with active sonar.

from my point of view, the big problem is trying to figure out how far and deep the passive sonar of escorts should extend. Now that we can "see" the escorts sonar, it is easier to figure out how it works and the impact tweaking can have. For example, this was from Ducimus's first WIP AI mod:




my boat is silent running at depth of 120 meters (390 feet) and the passive sonar of a veteran skill 1942 escort still extends out to 800 meters. It does not take much tweaking of the sonar ability or thermal leyer to create results which are out of whack. (note this is only for illustration purposes:this has now been cut back in the latest mod).

the problem is finding the happy medium so that it is not too easy or too hard, while maintaining the illusion of "realism" within the constraints of the game system.