Evading

[Scarredclown]

Its the second time that i attack a convoy and the escort depth charged me to hell. First time i was at periscope depth, launch my 4 torpedoes, then turn back and flee. I dive at 80 meters no result. This time i was waiting, periscope depth, silent running, i wait until they were close, about 1500 meters, launch my 4 torpedoes and i sink 3 ship ! hurray ! then i dive at 120 meters right under the convoy. I didnt have time to go very deep, i was depth charged at 40 ! What might work ? Crash diving ? isnt that to Noisy ?

[GoldenRivet]

what mods are you using?

[Pisces]

Don't take your time in going down (deep). Speed up if you have to. While flank speed might be a bit too noisy giving you away if you haven't been detected yet, medium or standard speed should get you down quicker. Diving rate is proportional to forward speed. They already know you are there if they are doing a trashcan run, so there is no need to pretend you are not there. Hurry down and then coast to a silent crawl in a clever direction. At depth you have more time to maneuver after the sound of dropping depthcharges are heard. It takes time for them to sink down to you. At periscope depth you are just a sitting duck.

I don't like to use the crashdive button. Because it forces your crew to go to a depth of 80 meters (iirc) which is a command you can't revoke. The crew still feels the need to go to that depth even when you command depth to something else. To undo it you have to go down to it. Also, 80 meters won't get you through the war. You can go deeper than testdepth with a bit of daring.

[GoldenRivet]

Destroyers have three methods of detecting you

1. visually with the watch crew

2. passively with hydrophones - they listen for the faint sounds of your engines, props, crew activities, various pumps and motors aboard the boat etc their ability to hear these things is affected by how far away from them you are, and/or how deeply you have dived.

3. actively with ASDIC - they send out a sound pulse or ping which reflects off the hull of the submarine and tells the destroyer where and how deep you are.

avoiding passive hydrophone detection is a matter of diving deep and maintaining your distance from the destroyers and by rigging for silent running.

avoiding ASDIC detection is a matter of reducing your aspect ratio relative to the destroyer transmitting the ASDIC ping. meaning that you should keep your stern or bow pointed as directly toward the attacker as possible because...

when you are pointed AT or directly FROM the destroyer his ASDIC "sees" this target (front or back view of u-boat)

<::>

the above is easily dismissed as a school of fish or bubbles or some disturbance in the water and thus, not something to waste depth charges on just yet

When you are at a 90 Degree angle to the attacking destroyer his ASDIC sees this target (side view of the U-boat)

<:::::::::::::::>

that... is unmistakably a U-boat and obviously what the destroyer should be depth charging the crap out of

as for diving deep... there are times when i will use a higher RPM like ahead standard or even Flank to gain depth as quickly as possible, but i wont do this unless at least one of my torpedoes has already hit... otherwise the convoy will start zig zagging before i have scored a hit. dont use crash dive while submerged because this may result in a bug which causes your u-boat to slowly descend when after reaching ordered depth

another thing you can do is dive as soon as your last shot leaves the tube. make sure you are rigged for silent running - otherwise your crew will assume it is ok for them to move forward with the VERY noisy activity of reloading the tubes. Destroyers will hear reloading activities from a mile away

Use BOLD decoy canisters if available. Once the destroyer passes overhead and gives you the first run of depth charges, deploy a bold canister as he passes then turn hard left or right at flank speed. as long as you are behind the destroyer you can make as much noise as possible to put distance between you and your attacker however he will turn around to acquire you and attack you again - this means you can only hold that flank speed for maybe 10 seconds. the hope here is that when he turns about, instead of detecting and attacking your boat, he will detect and attack your decoy. this buys you time to sneak away.

finally, 80 and 120 meters is not going to do it. especially in late war, i have had destroyers pound me down to 270 meters before. If you use SH3 Commander - the crush depth is randomized every time you launch the game to a more realistic number. A Type VIIC uboat for example - depending on the historical source of information used - had a theoretical crush depth of 250-275 meters, others estimate as high as 300 meters. this differs from "Test depth" or (red line) of 180 meters because Test Depth is just the depth they took the boat to while testing the prototype.

I've had destroyers push me down to 280 meters before in my VIIC

on important note to remember... Even early in the war, when destroyers were only just trying to figure out how to beat the U-boats, the destroyers still experienced some pretty stunning successes against the kriegsmarine.

as the war progresses, and you have one destroyer sitting still listening, while others ping you - thats when it gets really tough.

GWX is designed to be as historically accurate a mod for SH3 as possible... so just be aware, you have about a 75-80% chance of being killed at some point in your commander's career. especially after 1943

refer to GWX manual pages B-17 through B-20 for more information

[ReallyDedPoet]

Check out this thread:Here

Some helpful info there

[Scarredclown]

Thx all, i'm using GWX gold. In my next career i'll go deeper ! I've evade some ping before by turning my sub in the same line as the ship that hunt me. Now its time for my third career, hoping to survive for a whole year

[UKönig]

"3. actively with ASDIC - they send out a sound pulse or ping which reflects off the hull of the submarine and tells the destroyer where and how deep you are."

Actually GR, The one thing ASDIC cannot tell the operator is how deep you are. It can reveal direction, but not depth. They too must use their intuition or instincts to bomb the right place. If you have newbie HKs, you'll have a better chance of avoiding, but if you are on the hook by experienced crews, you will have to push your boat to the limits of its depth design.
By then, it won't be the bombs that kill you, it will be pressure hull failure.

In the novel "das boot", it is described as...(paraphrased)

...The enemy has us trapped in the tendrils of his direction finder. Right now, they're turning the handwheels, searching through the 3 dimensions with pulsing beams.
The ASDIC, I remind myself, is only effective up to a speed of 13 knots. Any faster and the destroyer can no longer maintain contact. At higher speed, the ASDIC suffers interference from the ship's own noises, including its propellers, which is an advantage for us, because it allows a last moment chance to change course a little. But the enemy captain knows that we won't stand still and wait for an attack, only, which way we move is the one thing his directional boys can't tell him. Here, he has to use his own instinct.
One more break for us is that our enemy and his clever machine cannot reveal how deep we are. In this, nature is on our side. Water is not simply water. Right down to our present depth it forms layers, like sedimentary rock. The salt content and physical conditions of these layers changes constantly. And they scatter the ASDIC. All we have to do is move suddenly from a layer of warm water to a layer of cold, and the beam becomes inaccurate. Even a layer of dense plankton can influence it. And the enemy above with their apparatus cannot correct their course plotting for us, because they don't know where these dammed layers are.

But once they've found you, and are pinging your boat, being quiet is no longer part of it. Might as well make all the racket you can and go deep as fast as you can. Go silent after a series of blasts and that will help confuse them as they search the depths, actively and passively to find you again.

Like Pisces and GoldenRivet said.



Don't be afraid to go down. It'll take some time and depth to crash the u-boat completely. And very often the depth is your only ally against the escorts. Always be aware of the depth under the boat. Always, if possible, avoid shallow waters like English Channel. (In my opinion, one of the most dangerous places for U-boats as the war progresses).

[GoldenRivet]

Originally Posted by UKönig

Actually GR, The one thing ASDIC cannot tell the operator is how deep you are.

In real life, from the initial development of ASDIC to 1943, ASDIC was only able to determine slant range to target. as the destroyer neared to within a few hundred yards of the target, they could develop an estimate of depth.

From 1943 onwards, ASDIC had been developed to include depth finders. The type 147 ASDIC and another device called the "Q attachment" only served to allow the attacking destroyer to determine the depth of the u-boat with almost certainty

While ASDIC was never developed during the war years to know the exact depth of the U-Boat, it was substantially developed by early 1943 to provide the depth of the u-boat to within a reasonable margin of error.

In GWX... they know your depth pretty much exactly.

[Scarredclown]

Originally Posted by GoldenRivet

In GWX... they know your depth pretty much exactly.

Since my last post, i manage to evade not once but twice the search following my failed attempt to approach the plump target in a convoy. It was on the same convoy the two times. I think i really pissed them off. After evading them , i go to periscope depth and at about 500 meters behind me was the warship and he was closing fast on me. I was in the right axis so i launch a torpedo and it explode just under the propeller sinking it. It was like striking a hornet nest !

Actually i get a little better at following a convoy and evading.

[UKönig]

In defense of 'das boot', it was written with 1941 in mind.
By 1943, allied anti-uboat weapons and sensors had been greatly improved and were very effective at finding and destroying submerged targets.
No doubt responsible for the majority of u-boat kills during this time.

[Aquelarrefox]

Originally Posted by GoldenRivet

In real life, from the initial development of ASDIC to 1943, ASDIC was only able to determine slant range to target. as the destroyer neared to within a few hundred yards of the target, they could develop an estimate of depth.

From 1943 onwards, ASDIC had been developed to include depth finders. The type 147 ASDIC and another device called the "Q attachment" only served to allow the attacking destroyer to determine the depth of the u-boat with almost certainty

While ASDIC was never developed during the war years to know the exact depth of the U-Boat, it was substantially developed by early 1943 to provide the depth of the u-boat to within a reasonable margin of error.

In GWX... they know your depth pretty much exactly.

hi
is there some mod to fix the sometimes "too acurate pinging" for GWX, worst data?

i have a question related with destroyer hydrophone. using gwx. weather afects their detection by hydro? i bealive that yes but im not sure if the speed of destroyer also decrease detection capacity.

yesterday i saw a destroyer, good weather, mybe 9000-10000, i go persicope depth. i saw later he goes 9-10 kt. in a moment i get flank, destroyer couldnt be nearest of 8000. Instactly start to zig zag and start the hunt. no deep water, type2, yah know im dead. How the hell it can detect me, its so noisy at 8000 the electric engine at flank?

An yes, when start to serch by group, the scape become to be a really problem. I dont undestand why uboats dont get some mines as countermeasure, if they drop some mines posible the destroyer would blow in the air during the serch or the pinging path. Mybe was too dangerous add some mines over the boat.

[Fahnenbohn]

Originally Posted by Pisces

At periscope depth you are just a sitting duck.

Yes.

[Von Due]

Originally Posted by Aquelarrefox

hi
is there some mod to fix the sometimes "too acurate pinging" for GWX, worst data?

i have a question related with destroyer hydrophone. using gwx. weather afects their detection by hydro? i bealive that yes but im not sure if the speed of destroyer also decrease detection capacity.

yesterday i saw a destroyer, good weather, mybe 9000-10000, i go persicope depth. i saw later he goes 9-10 kt. in a moment i get flank, destroyer couldnt be nearest of 8000. Instactly start to zig zag and start the hunt. no deep water, type2, yah know im dead. How the hell it can detect me, its so noisy at 8000 the electric engine at flank?

An yes, when start to serch by group, the scape become to be a really problem. I dont undestand why uboats dont get some mines as countermeasure, if they drop some mines posible the destroyer would blow in the air during the serch or the pinging path. Mybe was too dangerous add some mines over the boat.

What I have found is that even if you can hear the pinging, if it is weak, that does not necessarily mean they are on to you. Often you will not be detected. If the pinging grows louder however, then you have a situation.
Problem is a non situation can turn into a situation in just a couple of seconds, especially if you have your broadside facing the sonar.

Early in the war, diving to about 110 meters or more will force them to lose you early enough for you to have a good chance of either them missing your position or you having time to move out of harms way before the depth charges reach your depth.

Later in the war 110 might not be deep enough and in the last year or 2 you will have to put the crush depth to the test, to get away from their sonar/hedgehog combo.

As for their and your hydrophone detection range, I am honestly a bit puzzled. I have had merchants and warships at 5000 meters on clear days where my sound man could not hear the ship. On other days with poorer weather he picked up the ships at great distances. Depth should matter but I am not sure how consistent it is in the game.

There is something not right about their ability to detect you vs the noise you make vs the noise they make. I have managed to approach destroyers to about 2000 meters at 150 RPM while they were going medium speed, other times they detected me while I was at 50 RPM they going medium speed.

In real life, a destroyer going flank would only detect a submarine (except for sonar) if it crashed into one. Its own noise would completely drown any sound coming from the sub. In the game, they have been able to detect me while they were at flank speed and I was going full ahead, at ranges of about 8000 meters.

In short, it seems to me the game is a bit inconsistent when it comes to the AI's ability to detect by hydrophone. Sometimes it's somewhat realistic, other times the SH2 Marvel Comics Superdestroyers have made a return.

As for mines: In real life, the subs could be fitted to deploy mines but those would be more special operations missions. I don't think mines were ever used offensively or in self defence.

[Sailor Steve]

Originally Posted by Aquelarrefox

is there some mod to fix the sometimes "too acurate pinging" for GWX, worst data?

Not that I know of. I'm not so sure the pinging is "too accurate".

i have a question related with destroyer hydrophone. using gwx. weather afects their detection by hydro? i bealive that yes but im not sure if the speed of destroyer also decrease detection capacity.

I'm not sure, but I believe that is the case. They do seem less accurate in rough weather.

yesterday i saw a destroyer, good weather, mybe 9000-10000, i go persicope depth. i saw later he goes 9-10 kt. in a moment i get flank, destroyer couldnt be nearest of 8000. Instactly start to zig zag and start the hunt. no deep water, type2, yah know im dead. How the hell it can detect me, its so noisy at 8000 the electric engine at flank?

It's not the electric motors that make the noise, it's the propellers. Making revolutions for 8 knots is very noisy indeed.

An yes, when start to serch by group, the scape become to be a really problem. I dont undestand why uboats dont get some mines as countermeasure, if they drop some mines posible the destroyer would blow in the air during the serch or the pinging path. Mybe was too dangerous add some mines over the boat.

There were u-boats dedicated to laying mines. The problem isn't the mines being dangerous, it's that they take up the space used by the torpedoes. You can have one or the other, but not both. More mines, less torpedoes. And the mine-laying equipment takes up even more space.