Great historical tactic validated

[Freiwillige]

Okay I asked a few months back if coming in at periscope depth rigged for silent running was effective at slipping by escorts.:hmm: It has worked for me in AOD as they explaned in there manual that Asdic is less effective near the surface for two reasons.
1. Asdic is most effective pointing down at about 45 degrees. If you run at periscope depth you effectivly stay above that angle until the escort is about to ram you! (It would be luck or accidental on his part since he cant find you):ping:

2. Asdic is less effective near the surface because the ocean is not flat. Waves deflect the signals downward and scatter them. Obviously the the rougher the seas the better your protection.:know:

Okay on my last tour I had three seperate examples to try this on.

Example A. 70 Km east of the coast of England get a convoy report. I follow the coast south in rough weather and spot my targets. Periscope depth rig for silent and I sail in right past the escorts head on into the convoy. Depth under keel is less than 20 meters so diving isnt an otion anyway. Sank two heavy merchants and 3 destroyers were on me in minutes. Turn south and all escorts bracketed me in a triangle and pingin like mad men. None came closer than 200 meters and they were dropping DC's everywhere around me. I didnt even change course! They never got close and soon gave up and sped off after the convoy.:huh:

Example B. Same scenario 2 days later further down the coast of England. Only differance was it was daylight and smooth seas. Again my aproach brought me within 100 yards of a destroyer at that range he did ping on me for a split second when I was passing him at his and my 90 degree mark (Like cars on opposite sides of the road). He turned and promtly lost me even though I was so close I could have hit him with a rock and he depth charged 100 meters off my stern and swung around trying to locate me. He never did. Hit another two fatties in the convoy and again the escorts attacked by bracketing my area this time no less than five destroyers! circling and pinging I made a slight adjustent to my course to slip out of the widest gap in their bracket and sailed right between two without them having any idea where I was. Now I can garuntee you that if I went deeper they would be doing runs on me. But since they couldnt ping me they couldnt find me. It works!:up:

Note: this is in 1940

[iambecomelife]

What speed did you run at?

[Hitman]

Yes, that is historically correct :yep:

As the war progressed, ASDIC became more efficient near the surface, as passive listening also, but ultimately never efficient enough to prevent an U-Boat from penetrating the escort (Though running at peri depth meant in turn big chances of being spotted by aircraft). What in turn defeated the U-Boats was their unability to move quick underwater and place themselves in the proper position to penetrate the screen at slow speed. Forced down by aircraft, the only successes scored in late war came by aggressive commanders who by pure luck found themselves in the ideal position (in front of a convoy) to slip through the escort screen at silent running. And even then, once they attacked they would usually be unable to get out alive as they also lacked the necessary underwater speed for that :hmm:

[Lanzfeld]

Yes,

Historically correct but the real question, and I am VERY excited about his "research",

is this modelled in the game??????

I really want to test this myself as I creep around at P.D. but always dive when I think they detect me.

[Hitman]

AFAIK both GWX and NYGM model this to an extent. Since the SH3 sonar geometry is tweakable, you can decide which area itw ill cover, however IIRC you can't set a different intensity for different parts of that area. Anyway, I think that both supermods model sonar geometry in a manner that escorts will get a faint echo when you are at peri depth, but not the full echo. That is achieved by setting the minimum depth of the sonar beam to something that allows it only to see the keel of your U-Boat or such, hence giving a smaller return. So I would say that if you are presenting your bow or stern to a pinging escort while at periscope depth, he will not be able to locate you,

BUT

because SH3 units will only use one sensor at a time, if an escort starts pinging that's because he already detected you by other means -visual, by spotting your periscope, passive listening, etc.- so if you hear him pinging at you then you have already been detected and if you stay at peri depth he will ram you even if he can't locate you by active sonar, and once close enough he will be able to hear you anyway.

Therefore the use of this tactic has its limitations in SH3.

[Freiwillige]

Hitman-"because SH3 units will only use one sensor at a time, if an escort starts pinging that's because he already detected you by other means -visual, by spotting your periscope, passive listening, etc.- so if you hear him pinging at you then you have already been detected and if you stay at peri depth he will ram you even if he can't locate you by active sonar, and once close enough he will be able to hear you anyway."

When I was detected, I got greedy and and gave the ahead 2/3rds order. Once I was pinged it was back to 1/3 and was never detected again. Admittedly I was super close and careless with the destroyer that pinged me. I should have never gotten that close and deffinatly should not have tryed to zip past him at ahead 2/3rds! But He lost me about as soon as he found me.

Lanzfeld- "Yes,

Historically correct but the real question, and I am VERY excited about his "research",

is this modelled in the game??????

I really want to test this myself as I creep around at P.D. but always dive when I think they detect me."

Dont panic! By diving you are just revealing your location! Stay a shallow course and steer gently in the nearest exit direction. THey circle and many times it looks as if they have spotted you but turn at the last minute and start depth charging the area again. THis is them just trying to guess where your at because they dont know.:ping: :ahoy:
Well I use GWX 3.0 and I can tell you that it is in fact moddelled well. :up:

[Steeltrap]

Another thing that seems to be modelled to some degere is the effect of weather. While maintaining PD at low speed in bad weather presents its challenges, it seems to be true that the escorts' abilities to detect you are degraded.

My preference is still to attack on the surface until radar becomes common, because then you have all the advantages: small visual target and you retain surface speed + escorts can only detect you visually (ASDIC doesn't work if you're not submerged, which is why subs did such damage before radar).

[Freiwillige]

Yes I have done it again! This time heading out of Narvik Fjiord I came across a task force of 1 Battleship the Nelson and no less that 12 escort destroyers! I slid past the screen with ease and fired my ramaining 2 torps at the Nelson. Both impacted and the destroyer screen again circled all around me but never got closer than 100 meters! No pinging was heard but they circled like buzzards and I just kept my course. Oddly enough when I fired my rear torpedo I heard screws and swung my periscope around to find a destroyer blindly cruising on by 20 meters from me parralel to my course but going the opposite direction. After my torp fired feet of his starboard side he swung around but failed to find me. This really works Kaleuns!

Let me give you a graphic representation. This is them: :ping: :ahoy: :ping: :ahoy: :damn:


This is me: :rotfl: :up:

[Freiwillige]

And for one last time my test was effective making this tactic for me conclusive.

In the fiord leading to Narvik I position my boat to intercept an inbound fleet. Its the Nelson escorted by 8 destroyers. I put 4 into the side of the Nelson and slip at periscope depth righ through the escorts who are once again madly circling dropping DC's on emty water. I just continued north past the nose of the sinking Nelson while they churned up water south of me. again I was clear of their search screen in a matter of moments even though I got pinged once.

[gordonmull]

Hmm...I have had a different experience in two consecutive patrols. Running GWX3.

Twice I have approached two different convoys from the front, running 1 kt silent running mid and late 1940, first time in 0kt winds, second in 4kt winds. Admittedly this was at at 90 deg AOB to cvy course but at PD. Both times I was detected by the lead escort.

The first time I may have been ogling a bit much with the scope, possibly, but I try to be careful. The second time, because this was the only reason I could think of, I was being exremely careful to take small quick peeks.

Still, both times the eerie sound of those pings came through the hull. First time I put the scope up to see her bearing down on me and crashed dived. She ripped my conning tower destoying both scopes, my radio, well, everything in the tower. Returned to base after I evaded.

Second time I got out of her way. But now I was unhappy :stare: . I came back to to PD, took 2 two escorts out with torp spreads, one with the deck gun and severely crippled another, again with the DG. I was aiming to get an undefended cvy. Unfortunately the last escort sunk me marginally before I reckon I would have sunk her. One thing that amazed me was that the first escort I attacked with the DG. I destroyed her with three waterline hits at the bow and a couple of hits higher up on the hull.

OK not conventional but I was getting incredibly frustrated. All escorts were black swans BTW.

Anyway, sorry for the little sidetrack there!

[Freiwillige]

What year where you in Gordon as I have not tested this past early 40':know:

[gordonmull]

1st would have been late summer (July, August) 1940 and second was sept/oct.

It's happened a few times before and I've never made it past 1941. (Play DiD despite suicidal actions).

[Freiwillige]

Hmmm GWX 3? I just stay at PS depth and ahead 1/3 silent running and usually dont even change course. occasionally they ping me but never enough to know my exact whereabouts and usually when they do get a lucky ping as they swing around to attack they loose me anyways. I dont panick, I dont dive. I dont do much of anything other than minor course adjustments and just drive away as if nothing happened.:up:

[gordonmull]

The first time she had definitely caught me, I saw her bear down on me. I popped the scope up when I heard the pings. Second time I just crash dived, so maybe if I'd hung tight I might have got away with it.

What's making me wonder though is that I'm sure the escorts don't ping unless they've already found you in some way...

[Weiss Pinguin]

I believe they only use one sensor at a time, so it would make sense that if they're pinging for you, they've already detected you in some way.

[Freiwillige]

yes, they detected me when I launched my torpedo's and sunk their battle ship! So of course their gonna ping, Torpedos were fast and loud to a sonar operator. Doesnt mean that they know where you are though.

[Weiss Pinguin]

I guess that would probably tip them off :lol:

[Keelbuster]

IMO: staying at PD is good cover because of the angle of the ASDIC array (as said earlier). However this depends critically on the year (later you are jacked because they don't have the same blindspot) and the weather. In stormy or rough seas, you can run even at 2/3, loading torpedoes, and be fine at PD. But if you are deeper, you're burned. The surface is a noise area, so if you're below it you stand out. If it's totally still, they hear everything for like 2-3km around - if an escort is approaching you, turn everything off and shut up. In perfectly still water, even early in the war (and GWX 3 since i started anew!) I've been detected by an escort passing at about 6-700m. This won't happen in stormy weather. I had one run right over me (almost hit me) in high seas, and i was all schtop and he just steamed on.

On another note - sadly, torpedo firing makes no sound in SH3. Escorts never yell 'Torpedo in the water!'. If you sit in the center of the convoy and fire 5 wake-less torpedoes and none of them hit anything, the convoy treats it as if nothing happened. Worse, premature detonations also have no effect on convoy (or anybody's) alert status. What a bummer. Again, UBI made mistakes that no one can fix.

Alas, I still get killed pretty reliably in '44:D