Hmmm I managed few times to loose the chase without even a bomb near just by hitting the floor hard! It was in quite shallow waters like 60-80 so after hearing a DD coming over me and dropping bombs another Alarm and it finishes on the bottom because I forgot that I have only 30m left... So I hit the bottom and have slight damage but it sucks me in. I can't move so turn off the engines, fix urgent damages and be quiet... I works, they loss my track completely. I wonder if it would work the same way if I would sit on the bottom gentle. Time compression shows near land state in my case... May 1940.

EXACTLY.

You hear that Sebbe02?

I didnt manage to survive even in 1940. I loaded a previous game (undetected still) and managed to get to deeper waters avoiding detection. Note you are completely invisible if you are submerged, scopes down and stop. So if any warship would come close i would stop and wait till it passed me. doing this is rasoably easy undetected but i dont think i'll go to any shallow water port soon. I sank 20 000 tons while in the port but was not time efficient (specially in real life time) as you need to micro play your way out.

Its very hard in anything bigger than a type II uboat, but is possible. I got caught by a DD raiding a harbour in very shallow waters, got DC'd once or twice and did take some damage but if you do the wiggle waggle you can eventually get out of its grip. I think I was lucky but stick at it and keep you wits about you and it is possible.

Btw does the tactic of "playing dead" on the seabed actually work in GWX? IIRC the last time I tried it they dropped DC's right on my head resulting in instant death!

Note: I did this at the start of the war in '39, all I can say is RIP if you try this any later than 1940 lol

Mentat, relax man!:doh:

I was just suggesting an idea. I wasn't sure if I ever tried it myself, sure have played with the tought, but I don't know if I ever tried it.

The other tactic works for sure, that I am certain.

Within 300m no, torpedo will not arm. But it's possible to a swing around a DD and get a shoot from about 350m. Let the DD run a perpendicular pass above you somewhere at 50-60m depth. As soon as it releases depthcharges go flank speed, turn full rudder towards its path and order periscope depth. By the time you go up to 20m the sub starts levelling - raise the scope and turn engines full back - this will give you better separation from the DD to get more than 300m. Remember to switch rudder when going backwards. The DD will appear at about 60degrees offset, and torpedo heading almost head on. I don't think it's feasible to get a shot without automatic targeting - never been able to do it manually. Remember to set torpedo to fast, 0.5m running depth and open the tube before firing, you have about 3 to 5 seconds to get your shot.

Ive raided Scapa Flow a couple of times in '39 (found an aux. cruiser there :rock:)
and found a really easy way of escaping DDs is to stick really close to the coast and when the DD lines up for a DC attack, theres a good chance that they will run aground.

Bring up the scope and ready stern tube and one less DD on you. Havnt tried this in 40-41 though. I now have over 70,000 GRT to my name and its only November '39

This is realistic. Active sonar (known as ASDIC in WW2) works because sound waves tend to be reflected when they hit something with a different density - the larger the density change, the stronger the reflection.

So yes, the sonar reflects off the seafloor - but the density change going between the sea and the seafloor is much smaller than the density change between your u-boats pressure hull and the air inside it.

This means your u-boat acts amost like a mirror for active sonar - while the return from the seafloor isn't nearly as strong.

Sitting on the bottom will reduce the noise produced by your sub as there are no motors, propellors or pumps running, making you almost impossible to pick up on passive sonar (hydrophones), but makes no difference at all to active sonar.

In particularly shallow water I've often evaded being sunk because the DDs almost blow their sterns off with their own depth charges. I believe they have set the timing much too early and soon enough the DC sailors are flying through the air on their way to heaven :) If they survive, they continue to drop non existant DCs and the DD is pretty harmless after that. They still have to be shaken off though in order to surface. BTW this is with GWX.

Hmm, so boats sitting on seabed and evading DD's successfully in the movies are total crap then?

me too, but only in real shallow water. Otherwise, move and try to get in the dd's back. And alway have a torps ready for a quick shot. But you have to be really lucky to hit something.

I managed to escape 4 destroyers and frigates in very shallow water near the canadian coast in stock SH3. The just lost me somewhere after a wild chase.

Basically, yeah :D

As I said, sitting on the bottom makes you pretty much invisible to passive sonar (hydrophones) as it eliminates all mechanical noise, but it doesn't help you much against active sonar (ASDIC).

Sonar fish-finders work pretty much because the sonar signal bounces off the fish's swim bladder (an air sac inside a fish that it uses to control boyancy).

BOLD decoys deployed on u-boats work by releasing a mass of bubbles that creates a return on active sonar that looks like a u-boat.

And an ultrasound imaging machine is basically sonar, just at a different frequency. The image on the screen is basically showing the density of whatever is underneath the transponder.

Just got back from a harrowing mid-'42 IXC patrol to New York. BdU, in its infinite wisdom, sent me to CA28, which is all shallows just east of New York. I managed to sneak in to the square and set myself up guarding the entrance to the bay leading to the harbour, when a Large Cargo crossed my bow. With the sneering command of "Be more aggresive" ringing in my ears I dared not fail to shoot, and sink she did.

What followed was a 15 hour escape in 12-15m deep water with DD's and torpedo boats going ape**** around me. Going silent I managed to evade most of them for quite a while until a Clemson stumbled upon me, and immediately started pinging me. This led to a second DD approaching, and my big, hulking boat, barely concelead beneath the waves seemed doomed. I had six torps remaining tough, and through desperate manouvering and very poor marksmanship I finally nailed the Clemson with the last of the six.

But the other DD was still on me, doing several DC runs. The trick that worked best for me, apart from maintaining a small angle to him, running fast when he was pinging and constantly turning away from his charges was a liberal deployment of BOLDs. Firing off two BOLDs I went flank, turned so that the BOLD formed a barrier between me and the DD and set off at oblique angles in respect to my initial course. After doing this four or five times the DD ended up attacking my latest BOLD drop for several minutes - allowing me to flank off to reach the critical separation I needed to loose him.

So all in all, 1 DD sunk, 1 evaded, survived 3-4 DC runs directly over my position with 100% integrity remaining - still can't beleive my luck :) (GWX 1.03 100% realism btw)

I am playing in 85% (contact updates on,100% in GWX for some reason) I only use the contacts update because its enormously time consuming to manualy plot and very difficult to get an accurate range with the periscope/UZO.. Although, this means no instant id of a target, no AoB, no speed. Just a generic description like destroyer, patrol ship, etc if you get a visual or warship, marchant if you are using your hydrophones. If i wat to shoot i need to enter the time of shoot distance (range), calculate the AoB for each target, Jim's tools (included in stock and GWX) will only help you calculating the AoB if you are aprox 90 of an incoming target.
Then you need to plot, count one minute at least and plot again for a speed value (using the charts). Real life Captains and people who really go 100% still have to plot and calculate AoB based on aspect ratio and whatnot. Its very risky and prone to fail letting a valueable fish go at a 35knots incoming destroyer. I never shoot at escorts or destroyers.
AoB, range and speed may not be important if the destroyer is coming towards you at 0º or 180º but mind the fact torpedos need 300m to arm. And the very shallow chance you have to hit an incoming bow. Maybe magnetic fish would prove better at this, but still very risky and bear the 300m to arm. Do the enemy sub hunters zig zag? I remeber that was a mandatory tactic for any human playing a DD (Destroyer Command) against human U-boats, SH2.
My point is, if you play 100%, in shallow waters, upon detection your only hope is to flank and manover until you can dive deeper.Its often better in my experience to even avoid diving for a couple minutes to gain some more ground, until the splashes in the water hit your watchmen.

The DD's do indeed Zig Zag when going for final approach on a DC run. That is part of the reason I used six torps to sink one DD, the slimy bastard turned in the nick of time, everytime... Grr :)