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Old 12-17-21, 01:14 AM   #1
Zero Niner
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Default AI behaviour

June 1942, on patrol in the South China Sea off Hong Kong. It's night time and radar picks up a small convoy headed my way from the south, which turns out to be a CH-28 class sub chaser in the lead followed by a merchant ship astern.
I manage to get ahead, submerge and lie in wait. The escort passes me without noticing me, and I launch 2 torpedoes at the merchant, both hitting. The ship soon stops dead in the water, and I pass underwater to its other side but before I can manoeuvre into position to launch a 3rd torpedo sonar picks up another merchant coming my way from the north.
I deal with this 2nd merchant then fire a 3rd torpedo at the first merchant which sinks it.
Throughout this engagement, apart from firing a few illumination shells, the escort does nothing. It does not seek me out, or go to high speed to chase me down even with the 2nd merchant taking hits. It does not race to where it thinks I am and drop depth charges. Instead it just sits dead in the water (map says "stationary") and only starts moving slowly on its northerly course when the ship it was escorting sank.

I'm not sure if this behaviour is an anomaly or normal. I've not had many hours in FotRSU, but when I played GFO the escorting DDs would race towards me and drop depth charges. It would circle around stricken ships even if the rest of the convoy moved on. So the difference in AI behaviour is quite stark, to say the least.
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Old 12-17-21, 02:21 AM   #2
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Quote:
Originally Posted by Zero Niner View Post
June 1942, on patrol in the South China Sea off Hong Kong. It's night time and radar picks up a small convoy headed my way from the south, which turns out to be a CH-28 class sub chaser in the lead followed by a merchant ship astern.
I manage to get ahead, submerge and lie in wait. The escort passes me without noticing me, and I launch 2 torpedoes at the merchant, both hitting. The ship soon stops dead in the water, and I pass underwater to its other side but before I can manoeuvre into position to launch a 3rd torpedo sonar picks up another merchant coming my way from the north.
I deal with this 2nd merchant then fire a 3rd torpedo at the first merchant which sinks it.
Throughout this engagement, apart from firing a few illumination shells, the escort does nothing. It does not seek me out, or go to high speed to chase me down even with the 2nd merchant taking hits. It does not race to where it thinks I am and drop depth charges. Instead it just sits dead in the water (map says "stationary") and only starts moving slowly on its northerly course when the ship it was escorting sank.

I'm not sure if this behaviour is an anomaly or normal. I've not had many hours in FotRSU, but when I played GFO the escorting DDs would race towards me and drop depth charges. It would circle around stricken ships even if the rest of the convoy moved on. So the difference in AI behaviour is quite stark, to say the least.
Several possibilities or a combo thereof...


In stock/GFO escorts have best or close to it, in sound gear and sonar, so no difference between say a subchaser and a top of the line fleet destroyer. In reality, there was quite the difference especially until later phase in war. The top of line vessels such as destroyers received the best gear, a sub chaser like the CH-28 in 1942 would not have the best gear and probably not even the best of crews. So while he was alerted, could not detect you submerged so never had a fix on your location. Stock had a limited roster and made every ASW vessel the same basically. When he was sitting still, he was listening trying to locate you, you have been out of his hydrophone range. I had to adjust this in TMO 2.5 to solve this issue, it was happening too often. Mods such as FOTRS and TMO have various types of vessels. So facing a second line vessel with a likely unskilled crew, 1942 and all is likely the major issue.


Another factor could be the weather...sea state matters, if had choppy seas, likely made it difficult for them to locate you. If you were on silent running, that has an effect as well. It appears the way the sim does silent running is your sub has two types of electric engines, regular and then a "silent drive", when silent running is active, your sub operates on these engines and does not emit the normal noise. Unfortunately, if you're on silent running and some distance away , can make it difficult to locate. Then again in most situations one has to go to silent running during approach to get close enough to fire or will be heard. This can great situation where escort does not hear your boat even after alerted, even after sinking etc. This can make for anticlimactic and boring patrols if happens often. I usually cut silent running just after torpedoes hit, to simulate those moments when alerted escorts are searching, then when have to dive to rig for depth charge, rig for silent running and they will come to attack.


In summation...

You were facing a second line vessel in early war, likely the crew settings was set to competent or below. What sensors it does have may need tweaked to be a bit more sensitive if you got away with that much.
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Old 12-17-21, 06:24 AM   #3
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Thank you for the explanation. Makes sense. Yes, the sea state was moderately choppy and I was on silent runnng.
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Old 12-17-21, 10:47 AM   #4
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If you don't mind Zero Niner, what boat are you in, where did you sail from, and on what date. Also, do you have the exact date of the instance? If you could also post your mod list, if it is other than just FotRSU, including any mods from the AddInModzPak.

We'll double-check the CH-28. While it is a lower-class escort, it should have at least given some semblence of attempting to find you. Did you happen to measure the distance between the escort and the ship? What we have found is in some groups, the "escorts" are not really "escorts", but just happen to be in the area at the time the player is there. However, it still should be more "aggressive".
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Old 12-17-21, 12:20 PM   #5
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No problem. Here are the details:

Boat - Sargo class, based in Fremantle
Date - night of Jun 7 & 8 1942.
Mods - just 2, apart from FotRSU 1.46:
- Webster's 300' underwater visibility for v1.5
- FJB camera mod for GFO mod v1.1

Unfortunately I don't have a save of the attack to check the distance, but it definitely was a 2-ship convoy with the escort in front and the merchant in line astern behind. During my approach to set up the attack the 2 ships both changed course to a roughly northerly course - about 350 deg if I recall.

Hope this helps.
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Old 12-17-21, 02:32 PM   #6
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Had you purchased the SJ prior to June 1, 1942? We'll have to do some testing with and without the two other mods you have there, and see if they are influencing the AI behavior. I have never used them, and we had always just assumed the water mod was fine, with no one reporting issues, but I suppose we should test them eventually... we'll have to look at them from an ID conflict POV, as in Let's grab the ID's, and see if maybe we're accidentally "killing" the killers - or if maybe it is actually changing the sensor behavior...
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Old 12-17-21, 04:28 PM   #7
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Quote:
Originally Posted by propbeanie View Post
Had you purchased the SJ prior to June 1, 1942? We'll have to do some testing with and without the two other mods you have there, and see if they are influencing the AI behavior. I have never used them, and we had always just assumed the water mod was fine, with no one reporting issues, but I suppose we should test them eventually... we'll have to look at them from an ID conflict POV, as in Let's grab the ID's, and see if maybe we're accidentally "killing" the killers - or if maybe it is actually changing the sensor behavior...
With all the mod sets I've had (& still have the "less fog + water visibility +100/200/etc." mod, there... never had any issues... (that I can recall of...)

BUT... that could be in all probability, that I never used that:

- FJB camera mod for GFO mod v1.1

with them, either.

Still... probably wouldn't hurt, to put 'em through the wash/wringer means, that you outlined, either... just, to be as 100% sure as is possible. *shrugs*



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Old 12-18-21, 12:37 AM   #8
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Quote:
Originally Posted by propbeanie View Post
Had you purchased the SJ prior to June 1, 1942?
Yes. I departed Fremantle on this patrol on May 10 1942; prior to that I bought the SJ radar for my boat.
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Old 12-18-21, 10:00 PM   #9
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I don't know why I hadn't asked this detail, because it does loom large at times, but what depth were you at for the approach, the attack then at PD, and what depth was your egress? Do you remember the range to your target when you shot, and the approximate angle?

I have done several tests on the CH-28 with only FotRSU on June 7, 1942 1300 hours. I have the CH-28 facing north, engines at zero, not anchored, and I approach at PD from behind, from in front, and from the two sides. The behind approach, as expected, I was all of the way alongside the ship, roughly 300 yards off his beam, and he detects me as soon as my motors are alongside roughly his bridge area. He takes off in a straight line initially, drops four charges from the racks, then shoots four from the Y-Guns, which is what he almost had me with - I forgot about those things. Anyway, as soon as he started up, I went Ahead Flank and crash dive (from PD). As soon as I hear "Passing thermal layer" (184 foot), I go to Ahead One Third, hard right rudder, and call for 250 feet, going to Silent Running shortly thereafter, holding a course of roughly 30T then. The CH-28 circled several times, and dropped charges and shot with the Y-Gun just about the same place every time, but I of course, was well clear of that spot after his 2nd pass, and he didn't get close after.

Approaching from the front was not close to that. He kept chuffing his exhaust, and would move a few feet, then wait, like listening again. He heard me good enough apparently when I was still a bit out, and bee-lined me while I was roughly 2000 yards away. He basically followed me as I did a similar move as above, and did do quite a bit of damage on my boat. Instead of dropping four and shooting four, he would drop about 8 and shoot maybe a dozen, and seemed to vary the depth, making it difficult to decide what to do when he passed over each time. I did finally lose him, but only with the help of the external camera, and knowing which way he was turning each time, and I was finally able to put some distance on him by the time I exited. btw, I had gone below test depth with the Sargo after about his 3rd pass, and it still seemed like he was dropping them below me... We'll have to look at that for FotRSU. That should be later in the war.

The approaches from the side were similar to the front, only I did manage to get into about 1200 yards before he came after me. I had no problem with him prosecuting attacks. However, he was not "attached" to a group. I'll try some of those in a few days, but the ship itself seems fine. This is NOT an indictment of the other mods, just an initial observation. Testing with a group is needed. What I CAN tell is that the ship is practically deaf from behind, and from the sides up to about 1500 yards, during this time period. Just don't get in front of it, because it can lay down a LOT of depth charges, concentrated in a small area.

A few notes, but in 1942, the ship carries Type93-1P hydrophone ("P" for Passive), which are their "basic issue" device, and were not that good. The IJN didn't see the need for them. The sonar is Type93-1A, with the "A" meaning "Active", and is also not very good. I did not get pinged by the CH-28 but a couple of times, so I suspect they generally did not "know" where I was, since there was never a "visual" cue to go by to initiate targeting. Give them a periscope and / or a torpedo track, and that would probably change. No radar until 1944. More later.
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Old 12-19-21, 04:13 AM   #10
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Anyone know why sometimes the convoy goes haywire and starts zigzagging in every direction after being attacked? Not keeping a general course? Some even going in different direction?
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Old 12-19-21, 01:12 PM   #11
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If I recall rightly... some ships crews, would get... discombobbled... & go into full blown panic mode that resulted in a flight... or in this case, that ships all scattered behavior you're seeing, there.

Even weirder... had 1 warship-merchie mixed group I ran into... I did an attack on 2 warships that were prime targets of opportunity (per orders received after sending off a contacts report & got back, to hit the warships of the bunch... with a hearty "best of luck to ya nod from command." to boot.

Needless to say, I hit a light/heavy?? cruiser & 1 BB, out of 2 BB's & 3 cruisers...

group had like... 6-8 DD/DE's & on torps impacting on the 2 targets I went with... the main warships went to a dead stop... the merchies kept on sailing in the course heading they all were on initially...& those DD/De's...

they scattered to the 4 winds, apparently in an attempt to locate lil' ol Me.... never even came close... with maybe... just maybe... the exception of 1 of the DD/DE's... & even that wasn't spot on at that... just grazed by where I was, maneuvering to get into a killing blow spot to finish off the BB... that cruiser by then, had went to the bottom.

On hitting the BB I had targeted... the 2nd time around, the merchie's went Nutz, going Willy-Nilly & scattered to the 4 winds... just like your "convoy" there... Niume.

After I sank the BB... it looked to be that the group... tried to reconverge... if it succeeded or not... Dunno... as by that time... I did like the good shepherd said & got the flock outta Dodge.... stealthily, I might add...



M. M.

That was some time back... & can't rightly recall if that was in an earlier on version of FotRS-U... or another TMO mod set up... but do know it was in a SH4 mod mix... & was U.S. fleet boat mix, at that...
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Old 12-19-21, 09:04 PM   #12
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Quote:
I don't know why I hadn't asked this detail, because it does loom large at times, but what depth were you at for the approach, the attack then at PD, and what depth was your egress? Do you remember the range to your target when you shot, and the approximate angle?
I did an end around then submerged to PD to wait for them to pass me. Egress I think was maybe 100' - I wasn't looking to sneak away but position the boat for a rear shot.
Range to target would've been in the range of about 1000 - 1200', my usual range of attack. AOB would've been approximately 90 deg, +/- 10-15 deg.
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Old 12-20-21, 09:07 AM   #13
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Thanks, so you should have been in the "beam" when the escort passed by your location then... I'll try a few more tests in a few days, with a ship attached and with the other mods activated. Thanks!
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Old 12-20-21, 01:43 PM   #14
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I know zip all about how AI programming is done in SH.
However I have read widely on sub operations in the Pac, Atlantic and Med and one thing that has come through in all those books is that counterattacks varied from sometimes nil, as if the guy on the surface shrugged his shoulders and muttered "c'est la guerre" and motored on to sometimes rabidly aggressive pursuit lasting 12 hours or more like the mans life depended on his nailing the offending sub.
In short, not only does equipment and training matter, the level of motivation to prosecute an counter-attack also mattered, in real life anyway. Crew morale, rest level, ammunition level, whether the convoy was over/under escorted, convoy speed, the weather; all these factors would play a role in how determined a counter attack would be or if one even took place. In terms of the real thing at the time, your experience is not out of bounds or unrealistic.
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