How dangerous is to use active sonar?

[kstanb]

I am playing with TMO 2.5 +RSRD with no map update; and it is early in the war (radar is not available), so my question is:

in your experience, how dangerous is to ping a far away convoy? I am talking barely visible ships at more than 8 to 10K yards (stadimeter is useless there)

I have started to use sonar to try to figure out the convoy (or task force) course and range; and then position myself in their path; so for I haven't being spotted, and this approach has been less risky than closing (usually surfaced) to get a better stadimeter read.

thanks in advance

[tomoose]

IIRC there are previous posts asking this question. I don't think the En AI "hear" the ping but I've had a couple of incidents (in my early days) where I pinged and the escorts came a-charging. That could have been a coincidence however. If the En warship AI can't "hear" an active ping then technically it would be "cheating" if you took advantage of a game "deficiency" if you get my meaning. It's a personal choice in how you play the game.

Having said that, realism-wise, I doubt a sub skipper would actively ping if there were enemy warships anywhere around. Someone may correct me but the ONLY time I have used an active-ping is vs a solitary merchant and nothing else. Even then I rarely do it.

[kstanb]

But I read somewhere that in early war, they used sonar intensively; that they would not raise a periscope for fear of spotters, and therefore base their entire solutions on sonar; and as far as I know it is not possible to get a range without active sonar

[TorpX]

Originally Posted by kstanb

But I read somewhere that in early war, they used sonar intensively; that they would not raise a periscope for fear of spotters, and therefore base their entire solutions on sonar; and as far as I know it is not possible to get a range without active sonar

You are correct about range requiring echo-ranging; passive listening is not sufficient. Skippers were trained to make sound approaches before the war, but this tactic was abandoned almost at once. It stemmed from the results of artificial, and highly coreographed exercises where aircraft, knowing when and where to look for the approaching sub, were able to spot it. I think these tactics were predicated on using passive sonar only. AFAIK, there were no enemy ships sunk with these methods. Echo-ranging would give your presense away much faster than using the periscope, generally speaking. The periscope visibility is exagerated, IMO. The danger of having your periscope spotted is mainly confined to 1,000 yds., maybe 2,000 under ideal conditions.

In any case, I don't think echo-ranging works much beyond 5,000 yds or so. Within this distance, you should be able to obtain fair results with the stadimeter. I've never really used echo-ranging in SH 4, mainly because it was seldom used in RL. I'm sure it is possible to sink ships with sonar only (with some luck), but I think it is going about it the hard way.

[Sailor Steve]

Absolutely correct. I posted this on another thread not long ago.
http://www.subsim.com/radioroom/show...81&postcount=7

[Stealhead]

Though to answer the question there is no danger in using the active sonar in game the enemy AI does not "hear" it that was the case in older TMOs I don't think it has changed my guess is that it is hard coded.Not sure with 2.5 though I have never tried it I have tested the no danger of pining in the past and it was true I did that out of curiosity though I never had an interest in trying a sound based attack seems boring to me.

They will 100% detect your radar though if an enemy ship has radar detection capabilities so keep that in mind.

You could also consider attacking on the surface at night this is very possible in TMO and you can get pretty close if you play your cards right.You can spot a TF or convoy during the day and track it until darkness by which point you'll have pretty good idea of its layout and course once you have SJ radar this task becomes much easier and you can use the radar without fear of detection until well into 1943.This depends on what class sub you are skippering with an S-boat getting into a good spot can be fairly hard thanks to the low speed in any other class it will be much easier because you can usually exceed the speed of the TF or convoy in most cases and have enough speed to change if need be.Of course all well laid plans can easily be dashed if your cat decides to jump onto your keyboard at the precise moment for the glory of the Japanese Empire.

[gi_dan2987]

I've been reading these posts and feel the urge to toss in my two cents. Real WW2 skippers would have to know the exact position of their submarine at all times on their maps in order to make accurate use of the famous 4 bearing method. Unlike in SH4, real skippers did not have the luxury of having a little submarine icon move around on their map like it does in game. So that's why sound only attacks were rare and inefficient. Sound contacts could give you an idea, but much plotting would have to be accomplished prior to the attack in order for it to properly work.

In regards to the comment about echo-ranging; I use RFB 2.0 with SH4 1.5. I will track a convoy on my surface radar until I have a good idea what their course and speed is. I then set up, wait until they're within visual distance, and begin range/bearing readings with the periscope. I make any necessary adjustment to the TDC according to the information gathered from the plots, and prepare my torps for firing.

Now here comes the part regarding preference of attack. I find that pinging for range/bearing, adjusting AOB to match course, and firing is much more fast and accurate than rifling through an ID book with my scope up in the air. Especially at night when it's hard to ID ships and see masts and funnels. I suppose real skippers would do whatever it took to gain accurate solutions. If it's dark and foggy/rainy/etc, you aren't going to be using your scope to much effect now are you?

Now here comes some questions I have for any and all to answer:

1. Regarding active sonar, can all ships (including merchants) detect when they're being pinged and begin evasive maneuver/attack?

2. Comparing apples to oranges, what is more accurate, Using stadimeter and periscope to obtain final range/bearing or using active sonar? Which one is less conspicuous? What are the advantages/disadvantages to both?

3. Concerning radar (surface and air search), from how far can the enemy detect your signals assuming they can detect them?

The reason I ask question 3 mainly is because I just completed a mission where I seemed to attract Jap convoys and task forces like flies. I fired all 24 torpedoes and racked up 30,000 tons in a hurry, but they never stopped coming. I had to run silent at test depth for most of my return trip to brisbane in my Gato class. As soon as I would surface and kick on the radar, I started attracting flies. If anyone can help me out here that would be great. Cheers!

[Stealhead]

Well number 3 in my experience the Japanese RWR is far less than the max SJ range.The last time I experimented they clearly had me pegged at around 10~12 miles sometimes less might be different in TMO 2.5 with changes and what not but I imagine it is still not near as far as the SJs max range.It seems that some AC have very good either RWR or their own radar so late war if you get an RWR hit you had better dive if it seems to be an AC. I have never had the issue you mention with radar.You might have been near a carrier TF in which case you will have encountered alot more aircraft than you would normally seem to it may have seemed like they where seeing your radar they may not have been at all depends on the year once the RWR for the sub is available you know that some IJN stuff has radar if it was pre late 43 then they generally have no RWR.

Number 2 I have not tried in TMO 2.5 but I am pretty sure that it has been said in the past that the ability for the AI to "hear" pings is 0 and that this is hard coded.So you can ping all day long they will never hear it.If they are coming after you they have you pegged in some other manner.


Attacks using just sonar all seem to have failed but they did sometimes use a ping for ranging although most crews found the SJ to be the most effective way to estimate range the real thing could actually see the splashes of deck gun shells as well as sometimes pick up low flying aircraft.Later war they also had special sonar that detected mines this sonar is not in the game.

[TorpX]

1. Regarding active sonar, can all ships (including merchants) detect when they're being pinged and begin evasive maneuver/attack?

2. Comparing apples to oranges, what is more accurate, Using stadimeter and periscope to obtain final range/bearing or using active sonar? Which one is less conspicuous? What are the advantages/disadvantages to both?

3. Concerning radar (surface and air search), from how far can the enemy detect your signals assuming they can detect them?

1. Merchant ships and the like shouldn't be able to hear you. I don't know about escorts, TBH. I always just assumed they were "listening".

2. Active sonar will be more accurate. The stadimeter requires that the mast height of the target be known. This is not always the case. Also, there are visibility issues (graphics issues) to consider.

3. I would assume that if the enemy has the capability to detect them, they could do so to the edge of the horizon ( taking the mast ht. into consideration). Remember, it is always easier to 'hear' the original signal, than it's echo. That is, when you 'ping' a ship, you must be able to hear the echo, but anyone else in the vicinity, only need be able to hear the original 'ping'. In other words, the 'ping' is always louder than the 'echo'. This applies to radar, too.

I really have no idea why you would be encountering so many ships like that. Perhaps, you got caught up in a invasion traffic pattern. Are you using the RSRDC mod?



Edit: I see Stealhead has better information. You would probably be better off to follow his advice as far as SH 4 goes.

[Bubblehead1980]

Pinging when an escort or warship is nearby , talking 0-1000 yards, just not a good idea.Otherwise, they really do not hear it unless you do it often or you are trying to ping a merchant and the warship is nearby, the ping may hit the warship and alert them.I have pinged a DD before and it got his attention, just matter of distance etc

[gi_dan2987]

The date was late 1942, early 1943 and the hunting grounds were located in the area stretching from 500nm due north of Rabaul on a line heading NW to the area between Guam and Palau islands in the west. That whole area for a radius of roughly 500-750nm was just thick with convoys and task forces. Like I said, I expended all torpedo stores and half my gun ammunition before aborting mission and returning to Brisbane in my Gato sub. I was originally supposed to drop an agent off in Tsurusaki, but obviously that didn't happen. I wasn't trying to patrol that area at all, they just kept running into me as I tried to pass through the area on the way to Japan. Obviously I had no choice but to take down as many tons as possible, and I did so with a great vengeance. By the way, I'm running RFB 2.0 over stock version 1.5.

[kstanb]

thanks a lot for your answers;

I think I will ping an escort at close range to see what happen

[MattM1121]

Well, I guess since kstanb never came back to this thread, his ping test was disastrous.

Originally Posted by kstanb

thanks a lot for your answers;

I think I will ping an escort at close range to see what happen

[groomsie]

Originally Posted by kstanb

But I read somewhere that in early war, they used sonar intensively; that they would not raise a periscope for fear of spotters, and therefore base their entire solutions on sonar; and as far as I know it is not possible to get a range without active sonar

Actually, this is not correct. It isn't easy to develop the range via passive sonar, but it can be done. I used this while I was in the Navy for tracking subs with a towed array, but it was developed after WW II by Lt Ekelund (story here). If you have a smart phone you can use the Ekelund range application...

Now, it is true that this was not possible in WW II without active sonar...

[groomsie]

Actually as I recall we just referred to it as TMA (target motion analysis), and we also used the technique to come up with estimated range, estimated course, and estimated speed of the target using both passive sonar (for surface and subsurface) and detection of radar emissions (for surfaced targets).