Defeat Sonar

[larsonboram]

Is it possible to defeat the sonar from sub chasers by increasing and decreasing your depth while in silent running and going at 4 knots?

[TorpX]

There are 2 basic flavors of 'sonar' in the game.

1. Passive sonar.
This is often referred to as hydrophones. This amounts to the sub hunters listening for noise you make. You can reduce this possibility of being detected by going slow, say 2 or 2½ kn. 'Silent running' shuts down repair work, and stops things like torpedo loading to reduce noise, but if you go at 4 knots, you are still making considerable noise.

Surface wave action creates noise, so weather can interfere with the use of passive sonar.

Passive sonar gives a bearing, but doesn't give much information about range.



2. Active sonar.
This is sometimes referred to as 'pinging' or echo-ranging. Being quiet will not prevent the enemy from locating you here. The best thing you can do is to turn your boat to present a narrow profile, so there is less surface area for the sonar to bounce off of.

Active sonar will give both bearing and range, so is a more effective tool for locating subs.

Going deep, deep enough to be under a 'thermal layer' will greatly reduce the effectiveness of either type of sonar, but changing depth in itself doesn't really help. In either case it is better not to be too close to the searching ships.



I'm sure someone will be able to give more in-depth tips for the game.

[Hambone307]

TorpX has it spot on. When you are found, there isn't much you can do, but hope they miss.

My Method(s):

Deep Water (>100'):

1) If I am being actively "pinged", I will issue a crash dive. I will dive to about 50 feet below the thermal layer, stay at flank speed and make a turn to avoid the trashcans. (This is all while being engaged by active sonar + depth charges).

2) If I have completed an attack and NOT been detected/pinged, I will issue silent running, dive to about 50 feet below thermal layer, manually set speed to 1 kt and make a gradual turn to present a low profile to approaching warships. If, at any point during this, I am detected and pinged, I will raise speed to flank and make a more aggressive move to try to get out of the path of the warship before DC's are dropped.

Shallow water (<100'):

1) I avoid.

2) If I am in water that is less than 100 feet, I will dive close to the bottom. Once there, I will plot the shortest course to deeper water and attempt to get there quietly. I will run at silent running, 1kt speed, and listen to the warships until I am hit with active sonar. At that point, I will move much faster, just so I can get out of the way.

Things to Know:

1) When hit by active sonar, silent running is pointless. They know where you are at and will kill you faster if you just fart around at 1kt. You can move as fast or slow as you like at this point, the faster the better for evading the depth charge runs. Once they pass over, drop those RPM's and make a turn while using the speed you built up in evading the DC's.

2) Shallow water is also an issue: shallow enough and there is no thermal layer to help hide under (if you can even dive), and there is also not much time to evade depth charges. It is also easier for escorts to get those charges under you. If that happens, you can be literally blown out of the water (had it happen once). If you can, stay out of the shallow areas, such as the Java Sea. If you catch a target in shallow water, shadow them until it gets deeper, or go in guns blazing and then get out of dodge.

Hope this helps.

[Armistead]

Most important things I've learned, know the AI and how it works, what factors work in your favor and which ones don't.

Active sonar or pinging only happens if you get in their sonar cone, stay out of it, but you're profile plays a big factor how well they get a fix on you, so stay skinny, during an attack, try to keep your nose towards the nearest escort.

They are virtually deaf in heavy seas.

In deep water, like most I go as deep as I can and hit flank and outrun the charges, this works 90% of the time, some of the Type A or B type escorts with multiple Y guns and double roll offs can be more difficult.

In medium depth, 300 ft or so, if faced with several, I will get deep as I can and blow tanks and hit flank as they start the run, blowing tanks make u rise very quickly and usually they fix in the depth zone you're in when they start the run...almost always they fall way under me, go back down after the run, rinse and repeat.

in shallow water, 150 ft or so, i stay at half knot, when they start the run, I hit flank reverse, seldom can you outrun the drop, I add a hard over turn as I reverse to clear my nose of a rear drop off...works most the time. Course nothing worse than getting caught in shallow water with several vet Type escorts that drop about 24 charges per run. If around 150 feet, I may blow tanks to get almost to the surface so they will fall under, but you have to be careful, cuz almost impossible to not breach...under a 100 ft, usually you do before u can get her going back down and get blasted some on the surface.
Smart skippers only attack in shallow water in heavy seas and I prefer some distance, 3-5000 yards and try to haul my arse out of the zone the torps spawned from where they will search about 1000 yard circle...

[Majestik 909]

T orpx - where you finding these thermal layers? I am yet to encounter any!

[Rockin Robbins]

Sonar is defeated when the ship using the sonar is sunk! Beyond that--good luck. Torpx' guidelines are as far as you can go. Remember that when you are below a thermal layer the sound is not blocked. It is attenuated. So they can still track you if you are noisy.

We always talk about life in the sim being easier than real life sub warfare, but in the handling of thermal layers there's a wrinkle where we have it harder. Several times during the war, subs went below the layer and blew enough ballast so that the floated on top of the layer but were negatively buoyant in the water above. This let them shut down propulsion and ventilation systems with complete stability as they were surfaced as deep as the thermal layer. They could go completely quiet there. We don't have that option!

And now you know.....the rest.. of the story!

[TorpX]

T orpx - where you finding these thermal layers? I am yet to encounter any!

I usually encounter one between 100 and 200 feet. The depth they are at should be variable, but the game doesn't seem very good in this department.

Your crew should give you a verbal notice: "..passing thermal layer.."; that's all.

In SHCE, we had an actual bathythermograph, so we could see the depth, and amount of the temperature change. That was sweet.

And RR is right. They don't make you silent or undetectable. You shouldn't rely on them too much.

[Majestik 909]

Interesting! My crew has never advised of this....usually they say "Sir! We are diving too deep!"

I too have used all back emergency and some pretty dramatic "Y" turns, especially when attacking destroyers.

Ditto on blowing ballast to make dramatic depth changes.

Interestingly, I have had the best luck attacking destroyers from dead-ahead and dead a stern...attacking while submerged and using sound contact for targeting.