GWX Team - convoy screen thoughts

[MarkShot]

Dear GWX Team,

As always, thanks for your wonderful mod.

I don't know how much control modders have over the convoy screen formation and the screen's behavior.

An now my feedback ...

It is my impression that the convoy defense is too heavily weighted to the flanks and rear.

I can consistently slip by the screen at 25M when that screen contains 6-9 escorts. Typically, there will be two escorts positioned forward. However, one of two will be considerably more forward than the other.

Generally, screens are not that hard to penetrated if you have an accurate course for the convoy and then can key in on the single most forward escort. You side step that escort with three key techniques:

(1) Silent running at 1-2kts.

(2) Time (you arrive way in advance ... thus, despite your low speed) the long lead distance gives you time to position.

(3) Depth. At 25M you have enough slack to drift upwards while making 1kts.

Once you clear that single escort, the convoy is open to you.

Okay, how could this approach be made harder:

(1) More escorts leading.

(2) More forward area in front of the covered by escort motion.

(3) Randomness in escort searching as opposed to predictable swings back and forth.

Now, I am not sure that anything can be tweaked, but for #1. However, I would think #1 might be promising. I would assume that the convoy's greatest vulnerability submerged is from the front. Your sub is constrained on close approach to only 1-2kts. There is limited opportunity to thrust in from the flanks; and none from the rear. Even if a flank attack is feasible, it requires much more skill than a forward attack. Why? The forward attack is highly passive based on letting the convoy come to you. The flank attack requires substantial repositioning of your U-boat both in a relative and absolute sense.

So, I would tend to think that the convoy would put up a strongest defense if 50% of the escorts were allocated to sweep ahead of the convoy. Of course, this configuration might not be historic, but I think it would increase the challenge of attacking GWX convoys.

The vulnerability I see to such approach is the pop-up attack. I have heard that despite moving very slowly and deep that the u-boat can blow ballast and rise rapidly to attack without alerting the escorts. I personally have not used this technique. A less uniform screen might make this style of attack easier.

Comments?

[MarkShot]

An example of threading the eye of the needle with 7 escorts in early 1943.

As far as I can tell, this procedure isn't really getting harder as the war progresses. What is getting harded is getting away after attacking.

PS: You may comment on my use of map contacts and red lines for warships. However, doing without these aids would only make is more tedious, but not impossible to do. Since mainly, you need to key off the lead escort at the point. Once you learn how to do that, you can thread the needle.

---

I have received numerous requests to share this mod for GWX Red Lines. Actual credit should go to Rubini as I adapted his work when I was playing GWX 1.03. This also works with other mods which alter contact lines. Here is a link to the mod. No, need to PM me with an email address:

Right click and do a SAVE AS to your hard drive; unzip; use JSGME to install.

http://home.comcast.net/~markshot/tempimages/redline.zip

http://home.comcast.net/~markshot/tempimages/eye01.jpg

[GoldenRivet]

good technique is what it amounts to.

Try the exact same thing in May of 1943 and post the results :lol:

[MarkShot]

That was 01/30/43.

Everyone keeps saying tomorrow.

I just finished playing through that checkpoint as practice.

I also fairly easily escaped the DEs after the attack. The AI mainly allocated as single DE to attack me and another to stay close.

I think similar to SH2, DE allocation appears to be dependent on proximity to your supposed location. So, it seems that if you attack a convoy with 7 escorts, it doesn't mean that they will counter-attack you with 7 escorts.

[ToySoldier]

Hi out there!

PS: You may comment on my use of map contacts and red lines for warships. However, doing without these aids would only make is more tedious, but not impossible to do. Since mainly, you need to key off the lead escort at the point. Once you learn how to do that, you can thread the needle.


Excuse my question .... but where did you get the red line from????

I like to have them to!!!!

In diesem Sinne
Gott mit uns
Frank B. aus K.

[MarkShot]

I made a mod of mods to do that.

PM me an email address and I will zip it and send it to you. Simple JSGME mod.

[Tessa]

I've run into a few convoys like that between 43-44 and don't really see the need to make it harder, or add more escorts. By lying in wait virtually like a ghost you achieve a perfect tactical position for an ambush that is going to dish out some major damage. Same as walking into a MG42 nest, sending more squads forward to get gunned down just leads to more body bags, you either get a sniper or start tossing grenades once the position is located. Escorts have to act smarter and can't carpetbomb areas with depth charges.

Even if the escorts find you, they're still at a major disadvantage with friendly fire and creating potential collisions within the convoy. After you empty your tubes you can break for one of the columns and hide under a large noise tanker or such. Even without silent speed you can reload potentially till you've run out (though that usually requires taking out 2-4 of the escorts) from hiding. Though destroyers are nimble ships, maneuvering through the columns to find you makes them slow down and concentrate on moving before they can really start looking for you. Perfect situation is if you can cripple a large target enough that it will eventually get left behind by the convoy. Just hide under him then slip away. Being able to attack a convoy like that is extremely fun, yet still requires a lot of skill to stay safe. It's one of the few major vulnerabilities convoys have, being at the right place at the right time is no coincidence :up:

[MarkShot]

Well, I am threading the needle again. There is just about about 1km gap between the two leading escorts. If they weren't coming to me, it would be d*m near impossible to hit that gap while doing 1-2kts while they are doing 8-15kts.

The front door is the only way I can see to get in, but it is the front door which isn't locked much better than the anyplace else.

[Captain Nemo]

Perhaps you are too good!:D Your suggestion about deploying 50% of the escorts at the front surely would leave the back door open, even though I agree with you that attacking from astern of the convoy is a much more difficult proposition from a manoeuvrability viewpoint. As you also point out, changing the way the escorts are deployed would not be accurate historically.

I believe that most u-boats made their approach to the convoy from the front, like you describe. Once an attack had been made the escorts immediately put plan Raspberry into operation. This plan was designed to combat u-boats that had sneaked past the escort screen and got in amongst the convoy. It was anticipated that once they had launched their attack the submarines would dive deep and lie silent, allowing the convoy to pass overhead then resurface behind the ships. Plan Raspberry called for the escorts to double back leaving the convoy to sail on. The escorts would then move behind the u-boat's estimated position, turn and in sailing back to rejoin the convoy, cross over where the sub was supposed to be dropping several patterns of depth charges.

If I remember rightly, the other plan the escorts used was called 'Pineapple' or 'Strawberry' can't quite remember which.

Nemo

[Keelbuster]

Escorts in the front - they get you on the way in. Escorts in the back, they get you on the way out. Either way they get you:D

[MarkShot]

The primary mission of the escort is to prevent the U-boat from sinking merchants. Killing the U-boat is just icing on the cake. So, I would argue in favor of making the attack harder even if that makes the escape easier.

I think sweeping the front of the convoy is probably the single most important thing which the escorts can do to prevent attacks. Unlike other subsims, given the limitations on moving any faster than a crawl, the front door is really the only viable option for submerged attack. In other games, you can come in from the flanks at better than a crawl while sacrificing your battery for a shooting position. This just isn't possible with GWX2.

[MarkShot]

The back door is only open to surface attack. However, the existence of radar and accurate gunnery makes surfaced back door attacks pure suicide.

[Jimbuna]

Usually (IMHO) the best method is to lie in wait ahead of the convoy in as good a strategic position as possible to warrant as little movement from the sub as possible.

Ideally, let the convoy come to you http://www.psionguild.org/forums/images/smilies/wolfsmilies/pirate.gif

[Dowly]

Usually (IMHO) the best method is to lie in wait ahead of the convoy in as good a strategic position as possible to warrant as little movement from the sub as possible.

Ideally, let the convoy come to you http://www.psionguild.org/forums/images/smilies/wolfsmilies/pirate.gif

Hear the man, also to add to this, if you like to play it safe turn your boat so it's parallel to the convoy's course. That way the ASDIC has the minimum change of hitting you. :up:

[MarkShot]

I am going to start working on something new today.

Instead of trying to slip in the front door at 25M at 1kts, I am going to try to come in at about 220M at 1kts. I think this will reduce the chance of ASDIC if I fail to nail the gap in the screen. Also, if they do detect me, it will be good to be deep. If I nail the gap, then I will blow ballast and pop up. Silent, of course.

[MarkShot]

The pop-up attack is definitely doable. You got about 15 minutes diving and about 15 minutes ascending. For a big convoy, you have adequate time get pass the forward screen and ascend into the middle of it while watching for collisions with the observation scope.

[Jimbuna]

I am going to start working on something new today.

Instead of trying to slip in the front door at 25M at 1kts, I am going to try to come in at about 220M at 1kts. I think this will reduce the chance of ASDIC if I fail to nail the gap in the screen. Also, if they do detect me, it will be good to be deep. If I nail the gap, then I will blow ballast and pop up. Silent, of course.

How do you blow ballast silently (presuming of course your into a certain element of realism play http://img98.imageshack.us/img98/1817/thinkbigsw1yo4.gif

[MarkShot]

Actually, in timing it, I don't think there is much difference between hydro planes and blowing balasts while keeping shaft RPM at 100.

So, realism aside, it's about 15 minutes to come up and shoot.

I know that I will never meet the high standards of the GRP (GWX Realism Police). Not even if I get a waterproof laptop and play in the shower with subwoofers shaking the bathroom! :)

* Above said in the spirit of jest ... no real insults implied or intended.

[Jimbuna]

Actually, in timing it, I don't think there is much difference between hydro planes and blowing balasts while keeping shaft RPM at 100.

So, realism aside, it's about 15 minutes to come up and shoot.

I know that I will never meet the high standards of the GRP (GWX Realism Police). Not even if I get a waterproof laptop and play in the shower with subwoofers shaking the bathroom! :)

* Above said in the spirit of jest ... no real insults implied or intended.

Likewise Kaleun http://www.psionguild.org/forums/images/smilies/wolfsmilies/pirate.gif

http://www.psionguild.org/forums/images/smilies/wolfsmilies/thumbsup.gif

[Pablo]

The pop-up attack is definitely doable. You got about 15 minutes diving and about 15 minutes ascending. For a big convoy, you have adequate time get pass the forward screen and ascend into the middle of it while watching for collisions with the observation scope.
Hi!

As discussed in the GWX Manual, early war sonar has a shallow downwards-looking angle: a deep approach works well because you are below the sonar detection cone by the time you are in detection range. Late war sonar can look down at very steep angles, and so the escorts are more likely to detect you at closer ranges when equipped with these types of systems.

@Markshot: These sonars start becoming more prevalent in mid-1943, which is why everyone keeps telling you to try convoy attacks in mid-1943 or later. They aren't always there, but you will know when they are.

Pablo

[MarkShot]

Can you really have fun just pouncing on lone merchants?

For me, what I love about all these games is the stalking, the attack, and the escape. I realize that war isn't supposed to be "sporting", but for me I play this as a game. So, passing up the convoys just takes all the fun out of it for me.

[Pablo]

Dear GWX Team,

As always, thanks for your wonderful mod.

I don't know how much control modders have over the convoy screen formation and the screen's behavior. Hi!

We have no control over the escort formations except in scripted single- and multi-player missions. We have been able to get the escorts to vary their paths and perform an active search every once in a while.

An now my feedback ...

It is my impression that the convoy defense is too heavily weighted to the flanks and rear.

I can consistently slip by the screen at 25M when that screen contains 6-9 escorts. Typically, there will be two escorts positioned forward. However, one of two will be considerably more forward than the other. The AI puts the escorted ships into a box formation, and spreads the escorts around the convoy in a circular formation, with escorts equidistant along the perimeter of the circle. This is why there are generally only one or two escorts in the front of a convoy, but we are unable to change it since the formation-creation logic is hard-coded.

Generally, screens are not that hard to penetrated if you have an accurate course for the convoy and then can key in on the single most forward escort. You side step that escort with three key techniques:

(1) Silent running at 1-2kts.

(2) Time (you arrive way in advance ... thus, despite your low speed) the long lead distance gives you time to position.

(3) Depth. At 25M you have enough slack to drift upwards while making 1kts.

Once you clear that single escort, the convoy is open to you.

Okay, how could this approach be made harder:

(1) More escorts leading.

(2) More forward area in front of the covered by escort motion.

(3) Randomness in escort searching as opposed to predictable swings back and forth.

Now, I am not sure that anything can be tweaked, but for #1. However, I would think #1 might be promising. I would assume that the convoy's greatest vulnerability submerged is from the front. Your sub is constrained on close approach to only 1-2kts. There is limited opportunity to thrust in from the flanks; and none from the rear. Even if a flank attack is feasible, it requires much more skill than a forward attack. Why? The forward attack is highly passive based on letting the convoy come to you. The flank attack requires substantial repositioning of your U-boat both in a relative and absolute sense.

So, I would tend to think that the convoy would put up a strongest defense if 50% of the escorts were allocated to sweep ahead of the convoy. Of course, this configuration might not be historic, but I think it would increase the challenge of attacking GWX convoys.

The vulnerability I see to such approach is the pop-up attack. I have heard that despite moving very slowly and deep that the u-boat can blow ballast and rise rapidly to attack without alerting the escorts. I personally have not used this technique. A less uniform screen might make this style of attack easier.

Comments? Convoy formations changed over the course of the war; eventually, you would find one or two flank escorts per side and a rear guard, with the rest of the escort in front of the convoy. Some of these remained in formation; others prowled about in front of the convoy and could be ordered to track down any U-boat detected by HFDF-capable ships in the convoy.

We have tried to use historical formations in the historically-based single- and multi-player missions, but the escort AI is not as smart as the humans which it attempts to emulate, so even historical formations are not as effective as they were in real life: escorts rarely "prowl" anywhere, and generally stay in formation. They will not execute a "Raspberry," "Half-Raspberry," or any other historical escort response to a U-boat attack other than to congregate in the U-boat's general area and search for it; however, they will use one escort to track you while the others maneuver to attack based on the reports of the escort that is tracking you.

The Silent Hunter III convoy setup and operations AI limits our ability to put historical operational approaches into practice. We could double or treble the number of convoy escorts, but Allied technical advances can make that a very tough proposition after about mid-1943, when the Allies start getting more advanced sonar.

Pablo

[Madox58]

One other point.
It is, after all, a simulation.
No one can give each ship in game that one special thing.
The Human element.
An scort can only work with the AI the Game has.
It does not have a "Gut" feeling.
It has limited experence as the game defines it.
Those are very different from real life.
You find the holes in the game.
Nothing special there.
I defeat games all the time by finding the flaws.
You want a "smarter" AI.
I doubt you get one without going too far the other way.

[MarkShot]

Thanks for the explanation of how the AI works.

I have seen some of this myself, since when practicing in some of my saved checkpoints, I watch the AI on the surface after I am sure that I have given them the slip.

From what I have seen, there are usually only one or two active searchers. I use the word active here not in a sonar sense, but in the sense of driving the situation. The active searchers appear to continuously circle to see if they can pick you up as they make their circular run. If they don't trip over you, then they double back on the spot where they had you and drop another pattern. The other escorts sit more or less still at further distances, I guess either waiting for a report of your updated location or that you might foolishly pass directly underneath them.

I will agree that the AI is a bit weak. In a strategic sense, the addition of escorts doesn't seem to vastly complicate the sub's task of escaping. Having played AOD, going from 4-7 escorts can often be the kiss of death, because they form an impenetrable circle which you will never break out of. Also, they attack much more aggressively and force a great deal more movement to avoid destruction. Thus, you get maybe 10 good runs, before your battery has nothing left. I find that in this game, I can milk a battery for evasion for a very long, long time. Someone had once offered an analysis of I think SH1 and escort behavior showing how each escort contributes to tightening the window of escape such that by the time the 8th escort appears, the window is only about 10% of the circumfrence wide such that it is almost impossible to nail it and escape.

Thanks again. I'll continue to explore the game.

By the way, does SH4 play pretty much the same? I have it and mods installed, but haven't really been playing yet?

[MarkShot]

Bump - see screenshot. Added a place to download the redline mod for those who have been asking. Credit to Rubini as I adapted his work for my own personal needs.

Rubini, if sharing this is not cool, then let me know and I will take it down and stop responding to requests for it.

Thanks.

[Pablo]

Thus, you get maybe 10 good runs, before your battery has nothing left. I find that in this game, I can milk a battery for evasion for a very long, long time.
Long battery life is in line with historical capabilities. A Type VIIC U-boat could go about 80 miles at 4 knots, and the Type IX about 65 miles at 4 knots while submerged on a battery charge, so having a flat battery after evading only 10 depth charge patterns seems a bit on the low side to me. Historically, the hunter-killer groups just camped overhead until psychological factors or battle damage forced the boat to the surface or killed it.

By the way, does SH4 play pretty much the same? I have it and mods installed, but haven't really been playing yet?
Hmm... your best bet is probably to check the SH IV fora. IIRC the stock escort behavior isn't very effective, but modders have been tweaking things to make them more effective.

Pablo

[MarkShot]

The point I failed to make is that game play wise (I know nothing of realism), resource management; battery and compressed air have a much greater role in AOD than SH3. I've never really felt up against a wall in SH3 when it comes to battery charge or compressed air. For game play, it makes things more interesting and challenging when trying to decide what to do when time and patience are not the only factors.

[MarkShot]

I should explain. The 10 runs I mention in AOD isn't really for escaping patterns. That's 10 runs assuming that they have your position fixed. Once they have you fixed, running does no good. Your best chance to survive the pattern and break contact happens at the moment of the attack. So, during the attack you run to avoid the pattern, but you also do your most extreme and radical maneuvering, since you have a short window to break contact. You can avoid the pattern using a lot less battery, but for sure after 5-15 minutes they will detect you again. So, you use your battery in an extreme fashion to try to displace during the attack from your known position such that they fail to reacquire you. That's where most of your battery investment goes.

The best policy of course is never to be detected. Shoot and scoot. This is possible in AOD and SH1, since the passive sonar is not nearly the equal of SH3/GWX. So, when you have some distance, you can move at a good clip.

Once detected, the best policy is break contact as quickly as possible. The more escorts that form up in the hunt for you, the more rapidly your chances of survival falls. So, break contact when only the initial elements have you. Unlike SH3/GWX, they will all participate in hunting you down if given time. Also, escorts can easily invest 1-2 hours before sprinting back to the convoy.

Once the hunt for you is in full swing and they have contact, then you crawl along and try a slow feint in a false direction. Your ultimate goal is to try create a situation where multiple escorts immediately following the attack will tend to be grouped in the same quadrant. You will attempt to exploit this by using the temporary gap this leaves with them all clustered in one area. You must get enough distance from where they will resume looking for you before they rebuild the circle. You have to use the cover of the attack and good noise management to get this distance. If you do it right, they will fail to immediatly reacquire and they will fail reacquire when they widen the search after 15-30 minutes.

Both SH1 and AOD have good escort hunting coordination, but AOD is by far the best I have seen. AOD also makes screen penetration quite hard too. Not so much due to the passive sonar sensitivity of SH3/GWX, but their searching behavior which provides much better coverage and randomness. They always have their active sonar on, but unlike SH3 ... there is not a one sensor enabled limit. Visual, passive, and active can all be engaged at once. :)

Also, both SH1 and AOD truly prevent any accurate measurement of escort distance from your sub. All you have are some volume and pitch factors, screw sounds through the hull, and bearing rate of the contact arc. More deductions are required to play the game of cat and mouse.

Each game has differences in game play and AI strength. Thus, I play all. Beside graphics and sound SH3/GWX does offer game play challenges too. This is why I was eager to get to 1943. I wanted to stop simply counting tonnage and once again feel that my very life might be in jeopardy. For the moment, it seems to be.

[Pablo]

I should explain. The 10 runs I mention in AOD isn't really for escaping patterns. That's 10 runs assuming that they have your position fixed. Once they have you fixed, running does no good. Your best chance to survive the pattern and break contact happens at the moment of the attack. So, during the attack you run to avoid the pattern, but you also do your most extreme and radical maneuvering, since you have a short window to break contact. You can avoid the pattern using a lot less battery, but for sure after 5-15 minutes they will detect you again. So, you use your battery in an extreme fashion to try to displace during the attack from your known position such that they fail to reacquire you. That's where most of your battery investment goes. That was my assumption. Real U-boats could dodge under water for about a day or so before being forced to surface, barring damage or other factors that could force the U-boat to surface sooner. The convoy escorts were supposed to stay up with the convoy, and so would generally stick around just long enough to ensure the U-boat could no longer threaten the convoy; the hunter-killer teams did not have this constraint, and would latch on to a U-boat until the U-boat sank or surrendered.

This is why I was eager to get to 1943. I wanted to stop simply counting tonnage and once again feel that my very life might be in jeopardy. For the moment, it seems to be. OK, good. Say, if you're still looking for a challenge in 1944, and keeping to history isn't an issue, then I suppose we could always re-enable the "laser-guided depth charge" capability from stock Silent Hunter III, where the ASW ships always set their depth charges to explode very close to your actual depth.... :arrgh!:

Pablo

[MarkShot]

I have been doing more testing.

The deep approach followed by a pop-up attack on the outside of the convoy seems very effective. It allowed to use TC substantially without immediately being found. I got my shot taken and was able to get away without being localized. Finally, I was able to go deep and evade while maintaining 3kts.

Shallow approachs when combined with TC invariably met with being localized and pinging. As soon as I upped the TC, the escorts would accelerate towards me. Yuck - but I don't have four hours to approach in 1:1. However, the pop-up looks good.

[bigboywooly]

One of my favourite quotes


During exercises, Walker had evolved a form of attack known as Operation Plaster. It called for three sloops steaming in line abreast to roll depth charges off their sterns. Now he ordered Wild Goose and Kite to join Starling, and the three sloops steamed forward dropping a continuous stream of charges, the naval equivalent of an artillery barrage before an infantry attack. The sea heaved and shook under the impact of the explosions. Twisting and turning and always leaving a trail of charges, the ships plastered the area. In three minutes, 86 depth charges had rocked and shaken the attackers almost as much as it had U-202. The U Boat settled deeper and deeper, the control room crew watched the depth gauge. Down to 700. Much more and the submarine would crack under the tremendous pressure. 750. Poser's eyes would have been fixed on the controls, and his mind listening to the creaks and groans reverberating from the straining hull. 800, the engineer officer's will have warned. 850. Poser snapped out his commands: "Level off and keep her trimmed at 800 feet. Steer due north, 3 knots." Far above, Walker was talking to his officers: "No doubt about it. She's gone deeper than I thought possible, and our depth-charge primers won't explode below 600 feet. Very maddening indeed." He grinned and continued: "Well, long wait ahead. Let's have some sandwiches sent up. We will sit it out. I estimate this chap will surface at midnight. Either his air or batteries will give out by then." It was shortly after noon on June 13. By 8 p.m. Poser had taken several evasive turns without result. He could not shake off his tormentors. At two minutes after midnight his air gave out. He ordered reluctantly, "Take her to the surface." Without any audible warning, U-202 rose fast through the water to surface with bows high in the air. Her crew leaped through the conning tower hatch to man her guns, and Poser shouted for full speed in the hope of outrunning the hunters. On Starling's bridge, the tiny silver conning tower was visible in the moonlight. "Star shell...commence," ordered Walker. One turret bathed the heavens with light. Then came a flashing crash of the first broadside from all six sloops laying a barrage of shells around the target. A dull red glow leaped from behind the conning tower of the U-boat. A dimmed lamp blinked from Starling, and firing ceased while Walker increased speed to ram. Then he saw the jagged stump of the conning tower ablaze and shouted in triumph. U-202 was obviously too damaged to escape. He ran alongside, raking her decks with machine-gun fire and firing a shallow pattern of depth charges that straddled the submarine, enveloping her in smoke and spray. Poser clutched the hot periscope column, drew his revolver and shouted a last order: "Abandon ship! Abandon ship!" The cry was taken up and passed through the U-boat. Poser turned to say goodbye to his officers. But he found they too had all abandoned ship. So he dived into the sea, intend on their reprimand when the war was over. He had fully intended to de rather than be captured. At 12:30 a.m. the battle was over - 16 hours after it had begun.



http://www.mikekemble.com/ww2/walker.html

[Jimbuna]

I remember this piece well BB http://www.psionguild.org/forums/images/smilies/wolfsmilies/thumbsup.gif

You'll have to excuse me but I,m off now to count how many nuts and bolts it took to assemble those depth charges http://img98.imageshack.us/img98/2822/yawnbigji2wt7.gif

[Piter_]

Does redline mod work with GWX2? For me some how it did not.
I still have all lines grey :cry:

[MarkShot]

Does redline mod work with GWX2? For me some how it did not.
I still have all lines grey :cry:

Yes, it works fine for GWX 2. Since others have asked about it while I was away for a couple of weeks (sorry for the later reply):

(1) It has no impact on the color/shape of map plotted contacts. They remain grey.

(2) Contacts (both individual ships and groups) do not exhibit tails showing their course. However, individual ships when fully zoomed in do provide enough definition to plot precise course.

Link to mod is further up in this thread.