Evading deep?

[MarkShot]

I've been practicing some GWX convoy attacks using the single missions.

I know that anything about 1kts silent draws a lot of attention. So, it seems to me that I have two choices after shooting. Stay slow, silent, and shallow if I don't think anyone knows where I am. Or if I think that have my location, then make a noisy, crash dive, and go deep.

Given how long it takes to go deep when running slow and silent that would seem pointless, correct?

Is that pretty much it?

[deepboat]

If I'm a long time between reloads and I sense trouble, I go to flank speed send out some decoys if available and then make a hard turn stb or port, reduce my speed to slow or silent run and continue descent.

[UnterseeBoogeyMan]

if you are at 1-2 knots and can still hear you, try going to silent running. if you hear them come close, within short range and they are pinging, I would put as many crewman as I could in the bow, crank the engine full out, dive to 150 meters. at 100 meters depth I cut back to slow, silent running, and gradually make 10 degree turns in either direction. eventually they will lose you. If you are successfull at evading the DDs after their depth charge attack, you will be in the clear 30 minutes later becuase they will race away to catch up with the convoy.

I always run to te depths if they ping. the whole reason they ping is to get a bearing ,depth and range on you. they dont need to hear you to do that. if you go past 100 meters, their pings are not very effective.

I will be honest, my careers so far, have not gone past 1940, so mayb the tech of active sonar improves. but those are my observations on early war detection.

[The Butcher]

You are going to get swarmed as soon as the torpedos start exploding. Get deep while you can, I go flank speed, and if I can get below 100 meters I go. If you can't get deep then as long of of shot you can make and try to slip away silent. Good luck.

[rizZO_77]

I always go deep and silent after i have shot all my tubes. Reload and have another go if not detected. Otherwise i will try to creep away with silent running and try to overtake the convoy again from a safe distance.

[Brag]

Read the articles on convoy attack and evasion in my webbie. The methods work in SHIIIstock, GWX1.03 and GWX 2.O :D

[Jonathan]

I love all this information...I am smackl dabin the middle of trying to vade depth charges right now...

[Canovaro]

I go silent and deep, but ut takes a lot of time to reach 150m.
When they found me with asdic (about 20% of the time), I go full speed, and turning then try to go silent again and see if they lost me.


When diving at high speed, be very careful not to cross the depth line where you can't get your boat to rise anymore at slow speed!! You will sink deeper and deeper unless you increase speed, alerting the enemy.
This depth line depend on the boat you are using.

[Cohaagen]

I rarely offer advice to anyone on any subject, but here is this...

If the sea is rough (10mps+) - try staying at periscope depth/silent run. Their active/passive ASDIC readings will be seriously affected.

[Sailor Steve]

Cohaagen, that's great advice!:up:

I usually just crash dive to 70m, as that leaves me room to go deeper, as well as speeding up and turning right before they drop. Changing three dimensions is better than two.

[3Jane]

1/3 ahead until the first torpedo impact then to 2kts.

[Commander Gizmo]

I wonder if anyone else has tried this. If I have only one DD on my tail and an aft torpedo left, I will sometimes stay silent and turn rudder 30+ degrees in the direction the DD is circling. I find that they have a very hard time getting on top of me if I stay with them and then change to 30+ degrees the oposite when they start a run. Usually within 30 minutes I've got the aft torpedo under them and I've got the convoy all to myself.

[Philipp_Thomsen]

A lot of people think that the speed you're travelling underwater is the key to be stealthy... thats not quite right.

Doesnt matter how fast you're going, what matter is how fast your screws spinning. If you stay lower then 100 rpm, then you'll be undetected by hydrophone, they can only find you by pinging you (considering you're not reloading torpedos and/or fixing damaged systems).

I go around 3 or 4 kts, but keep my screws at 150 rpm maximum. They can't hear me. And if they find you, dont rush to the bottom using fast screws... that only gives them more and more clues about your position. Stay as quiet as you can and go deep, as deep as you can. I usually try to kiss the bottom of the sea, around 200-250 meters, leaving 5-10 meters below keel, so the DC that blow in the bottom dont damage my boat. The deeper you go, the harder for them to determine your position and the easier for you to evade DC, coz you have plenty of time to change your XYZ position.

I use to stay at periscope depth until the absolute breaking point, scoring the maximum tonnage i can, reloading torpedos as fast i can and releasing them. When its about dive or die, them i go totally silent and the deeper i can. If you can use the hydrophones well to determine where are they coming from and you're very deep, the chance of being depth charged are reduced to a very safe level, so i dont waste any oportunity to score more hits.

But be aware! If you're hunting in shallow waters (50m or less), forget about reloading the torpedos. Stay as quiet as you can, attack from a greater distance (2 or 3km) and get out of there before they find you. In shallow waters, any tonnage is already a big prize. In deep waters, take the risk, it's worth!

[MarkShot]

I know to manually set speed by the knot, but how do set your RPM?

Also, how can you set low RPM, but 4kts travel? Without a variable pitch prop how can the two be independent variables?

Thanks.

[Philipp_Thomsen]

I know to manually set speed by the knot, but how do set your RPM?

Also, how can you set low RPM, but 4kts travel? Without a variable pitch prop how can the two be independent variables?

Thanks.


They are not independent and you cant set the rpm manually... but setting the speed makes changes on the rpm dial... so you set your speed as much as you can while inside the maximum stealth rpm. You can see this dial better in the periscope tower (between the command room and the conning tower).

[MarkShot]

Yep, I saw these gauges by clicking on the engineers view and then panning to the right look over the steersmen.

[DS]

I have a pretty standard set of precedures that see me through:

1. Take the shots I've going to take within 2 minutes of game time (sometimes you have more time before destroyers are coming for you, in later years, usually not). If any escort is bow on to you and making speed in your direction, start your dive. Every moment you delay increases the odds of you taking hits during your dive, which will impeded the successful conclusion of this procedure, and your life.

2. Run at flank speed and emergency dive (tanks flooded) to 120+ metres. Do not worry about silence at this stage, especially if they have any inkling as to your location. If they know where you are, they know where you are, so no sense in being quiet.

3. When arrived (not while still approaching) at designated 120 +depth, set to "ahead slow and rig for silent running." Do NOT set silent running before arriving at your designated depth, as (in my experience) you will continue past your intended depth and then past your crush depth, despite all efforts short of turning off silent running. I believe this is due to the silent running command preventing the pumping of excess water ballast from your emergency dive procedure. In short, arrive at your 120+ depth first so your diving officer can adjust ballast with pumps, then set silent running which shuts down the ballast pumps.

4. Immediately after setting ahead slow and silent running, but while still having 6-7 knots of momentum speed from your high speed dive, change direction by 30+ degrees and creep away unmollested. (Depth charges may drop in your neighborhood on their first couple of runs, but they don't really know where you are once going silent, and every run they make, you are farther away each time).

This method, if successfully completed, gets me away 99.9% of the time from 1939 - 1943. It might work in '44-'45 as well, except that you are less likely to be able to complete the steps before being impeded in the manners noted below:



Impedaments to this procedure:

1. You had existing damage, or take damage before reaching 120+ metres, that prevents you from taking your boat that deep and living to tell about it (ie: you crush due to structural damage before or after arriving at 120+ metres)

2. You take a lucky hit (from the DD's perspective) in the first run or two while you are still in the immediate area of where the DD's last heard you. This hit either kills you, forces you to come shallower (flooding, structural damage) which sets you up for further hits, or forces you to increase spead to maintain depth control when flooding), which also allows them to hear you again and make successful follow on attacks.

3. You made your attack from a position with less water depth than your ordered dive, or less than 120 metres depthc in total, and had to level out shallower, or hit the bottom rather than leveling out (done this a few times :damn: ). "The captain ordered EMERGENCY DIVE TO 130 METRES! Unfortunatley, the water depth was only 50 metres. The first noise we heard was us hitting the bottom at high speed. The second noise we heard was the sound of hull scraping and flooding. The third noise was the sound of depth charges exploding all around and over our extremely noisy, shallowly bottomed and already flooding boat. We did not live to hear a fourth noise....)

[3Jane]

I know to manually set speed by the knot, but how do set your RPM?

Also, how can you set low RPM, but 4kts travel? Without a variable pitch prop how can the two be independent variables?

Thanks.

I find that three knots will keep the rpm at 150. Not a huge improvement over the 2 kts, but it all helps.

[Cohaagen]

Cohaagen, that's great advice!:up:

I usually just crash dive to 70m, as that leaves me room to go deeper, as well as speeding up and turning right before they drop. Changing three dimensions is better than two.
It works for me, man :D! The other advantage about rough weather PD is that you can raise your scope and, using the map (F5), spot when you are in the baffles of the pursuing escort - typically 150 degrees + AoB on either beam. Clicking on him will bring up the overlay. At that point you can ring up flank and increase distance.

The game doesn't model things like the effect of silent running on pumps and such as AOtD did. If you go to flank at depth, they can hear you. I've tested this - escorts always depth charge the last position you were detectable at before going silent.

Rough weather is the only environmental variable I've found that significantly affects AI hydrophones, and only when you're running shallow.

[Tobus]

Rough weather is the only environmental variable I've found that significantly affects AI hydrophones, and only when you're running shallow.

I have to disagree with you there. I have been found deep more when just running 2 kts, then when running 2 kts in silent running. This is regardless of the weather.

[Cohaagen]

By "environmental" I was talking about things like trying to hide on the seabed, hide under merchants and in convoys, and so on - things that people believe might mask sound (but don't). Might not have been the best word to use. Yeah, silent running obviously makes a big difference, but my point is that when the weather is really bad the surface is often the best place to be, particularly early in the war.

[difool2]

One problem I ran into (with the XXI, but applicable I assume to the other boats), was trying to run past test depth at silent running-I would just keep slowly sinking unless I upped the horsepower past ~1500 RPMs, which of course porks my silent sonar profile.

[Cohaagen]

You've just not got enough forward motion, and water passing over the hydroplanes, to maintain depth. In real life the XXI had a special "creep" motor for silent running.

[Jonathan]

I have found that no matter how slow I was going, they always found me. I have been fighting this for three days now. I go slow and deep, they find me. I stay high and fast, they find me. Etc., Etc., Etc.

I guess sinking the Nelson makes them upset! :rock:

[MarkShot]

I meant to ask about this.

GWX implements positive buoancy and so at PD, you will tend drift up and broach if you don't maintain at least 2kts.

However, if I take my VIIC deep to 220M, I find that even at 3kts it continues to sink with negative buoancy. I need to make at least 4kts to avoid sinking into the abyss. Why is this? Is this something about GWX or SH3? Is this modeling that air in any trim tanks would be much more compressed at that depth, and so, the same trim tanks would be taking on more water and make the sub go negative. Except for speeding up, there doesn't seem to be anyway to bleed any high pressure air into the trim tanks.

???

Thanks.

[MarkShot]

It looks like to maintain depth, you need the following speeds:

15-100M @ 2kts (positive)
100-150M @ 3kts (negative)
150-250M @ 4kts (negative)

[Jonathan]

Man, I have alot of information here...I hope that I can keep this stuff straight when the times comes. Going low and then silent and still has not worked for me. Whoever trains the ASW personnel are REALLY good because they can hit me at 120m. I also have to give it to whoever designed the Tybe VIIB...that is one tough boat.

I have my save game at the point where I am about to shoot my eels into the convoy 2000m away. So far. after every encounter, I ususally sink the HMS Nelson, a Large Cargo, and another ship whose name escapes me that weights 11,257 tons. But then I am sunk by the ASW ships.

Strange thing...last night, after staying alive for 12 hours, the ASW ship EXPLODED out of nowehre. Anyone have any idea what happened? :doh: Not that I am complaining...but by the time it was gone, my entire topside was gone, flak, conning tower, and deck gun...all dark red.

[SurfnSea]

A lot of good ideas given above. One idea I use, in conjunction with some ideas already given, but have not seen yet is:
When I'm deep and trying to evade I will go at Full speed until the moment I get the "Depth charges in the water sir!" At that exact moment I go to Flank. I figure that if they know my location and think they know where I'll be when the DCs explode then changing speed will change the location perhaps enough to make a difference on being sunk or surviving.

[Tobus]

Jonathan,

in most cases, depth is your friend. This is because ASDIC on escorts works in a "field" in a fixed angle from the ship. Therefor, the deeper you are, the farther away an escort looses your pingback from its ASDIC. So to a much longer time and degree, an escort then has to guess where you are when he presumably passes over you to drop dc's.

Therefor: when te pinging stops when an escort approaches you: ahead full flank if you aren't already, 10 meters deeper if possible and right/left full rudder, making a knuckle of 90 degrees to your original course.
Because of the depth, the dc's also take some time to come to your depth, so odds are that:
-a. you are not at the place (or even ever were) where the dc's explode
-b. you are not in the place where the escort now expects you to be.

After the explosions, go back to silent. With luck, the escort turns away in the same direction you did, so you have some time in its baffles, further decreasing the chance he will pick you up again.

The fun really starts when multiple escorts work together, one of them keeping contact while the rest makes accurate passes (since they now DO know where you are all the time, also on final approach). In my experience, EVERYTHING you do should be geared towards avoiding just that, even more so than sinking tonnage.