Is there a reason we don't get hydrophones for our battleships?

[disc]

2 hours ago, Shaftoe said:

Why? Did they extend out of the hull and couldn't handle incoming water pressure at higher speeds? Otherwise there's no need for a ship to go so slowly in order to use them.  However, if it had particularly poor hydrophone, then it might not have been effective. You need to be a little more precise with your wordings.

 @HusariuS was very faithful to the source material.

From Skulski, Anatomy of the Ship Yamato: "Yamato was equipped with Type 0 sonar arrays which could detect a submarine when the ship was dead in the water or proceeding at low speed." The diagrams Skulski provides show the apparatus was placed in the forefoot, in the ship's bulbous bow. 

That's it, unfortunately. No other information that I know of on Yamato's particular setup or its usefulness during various actions. Lengerer and Ahlberg's book on Yamato does not mention the sonar -- though I reckon this is due to its more narrow scope.

 

We do have more information on the Type 0 installation.

https://pacificwararchive.wordpress.com/2018/04/21/reports-of-the-u-s-naval-technical-mission-to-japan-1945-1946/

See E-10, Japanese Sonar and ASDIC. The Type 0 was a passive (ie hydrophone) 30-element double-ellipse (4m across the long axis) array using moving-coil receivers (I have not seen a picture of the hydrophone array, but my impression is it might look like two nested ellipses of individual receivers set around the bottom). It had an accuracy of 3 degrees and a sensitivity of 35db. Detection ranges are not specified, but the broadly similar Type 4 could detect a slow moving submerged submarine at 1000 meters, or a torpedo at 6000 meters, the scanning ship sailing at 12 knots in either case. The Type 93 was a very similar device to the Type 0, more common, with 16 elements in an ellipse array using moving-coil receivers, with an accuracy of 5 degrees and a sensitivity of 35db.

[disc]

I do not know how the Type 0 or the similar Type 93 would usually perform, or if they were particularly useful at picking up incoming torpedoes, but I think they didn't help as much as might be hoped. It does appear they were regularly operated at sea, but I don't know if they were reliable, if they were operable at high speed, or if the operators were competent.

Many Japanese cruisers used the Type 93, but many of these were torpedoed and sunk. Obviously hydrophones are of little avail against aerial torpedoes or point-blank submarine shots, but at least Haguro was sunk by surface torpedoes. Maya was sunk by multiple submarine torpedo hits at about a range of ~1.5 nautical miles (~2.8km), after having witnessed Takao and Atago get hit ~24 minutes prior -- ie obvious forewarning of submarines was there.

[Hangar18]

5 hours ago, Shaftoe said:

Why? Did they extend out of the hull and couldn't handle incoming water pressure at higher speeds? Otherwise there's no need for a ship to go so slowly in order to use them.  However, if it had particularly poor hydrophone, then it might not have been effective. You need to be a little more precise with your wordings.

not only are you going to hear the water running over the mic, but you are also going to be hearing the massive engines. In terms of detecting a ship, you would need to be going very slow. Torpdoes make a very high pitched noise, and you would be able hear those.

 

4 hours ago, Shaftoe said:

You can't see torpedoes in the water until they are "detected". The game hides them from player's view.

you can watch the other ships, and see when they drop torps. theres also an audio que

[arkhangelsk]

@disc First, on the problem of operator proficiency

From 25歳の館長海戦記 - the key takeaways being Type 93 sonars being installed in mid war refits on destroyers are half-sunk by torpedoes, and three weeks of crash training.

Maya did get hydrophones before her sinking, but it did not stop Dace from plugging her with torpedoes. As CombinedFleet.com puts it:

 

At 0555, LtCdr (later Captain) Bladen Clagett in USS DACE (SS-247) fires six torpedoes at 1, 800 yards at what Clagett takes to be "a KONGO-class battleship". At 0557, four torpedoes hit MAYA portside. One in the foreward chain locker, another opposite No. 1 gun turret, a third hits No. 7 boiler room and the last hits in her aft engine room. HAGURO evades the other two of DACE's torpedoes.

Well, at least one of them managed to dodge. The torpedoes that first hit Haguro were from Verulam fired at about 2000 yards so the problem may well be less a problem of detection than reaction. Besides, sonar of that time period are directional so if for any reason they aren't pointed in the right direction ... well... they aren't a panacea, but they are arguably useful.

18 hours ago, madham82 said:

That just highlights the real issue, you would only get a bearing...no range or speed. Hydrophones in these cases would have only put the crew on alert that they had been fired, and to keep eyes on that bearing to spot the wake (the only real way to plot them). The current method by which torpedoes are detected plots them exactly on the map (speed, range, bearing, with continual tracking) the moment they are detected, so it is easy to plot avoidance then.

I don't have an issue if eventually the hydrophone detection is altered so we get more of a bearing line than actually seeing the torpedoes. And BTW, I'm not saying they have to necessarily give me Sonar IV. But darn it, as long as they keep sending us out in lone battleships and the few times we have escorts we didn't get to build them so we don't know if they actually have sonars, I think we deserve at least Hydrophone I or II.

Edited March 23, 2020 by arkhangelsk

[Shaftoe]

14 hours ago, disc said:

 @HusariuS was very faithful to the source material.

Do I need to say it again? My question was: was that limitation a technical in nature, or simply dictated by effectiveness of the device?

Difference being:

1. Technical limitations required dead stop or dead slow in order to operate without damage. For example, subs must retract their masts when they dive, or when the mast is facing water pressure of over 5-10 knots - or it will become damaged. 

2. Effectiveness is another matter completely. While there is no risk to the device above designated speed, it simply will not be useful at its role.

First kind of limitation makes it useless for torpedo detection. Second limitation will restrict its use for contact detection and tracking, but will still allow to get a bearing on incoming torpedoes - which is what we were discussing.

I hope now you understand. 

[disc]

4 hours ago, arkhangelsk said:

Besides, sonar of that time period are directional so if for any reason they aren't pointed in the right direction ... well... they aren't a panacea, but they are arguably useful.

I think hydrophones of the style installed on Yamato and the heavy cruisers would be omnidirectional, with phase-cancelling used to find a bearing. So that would be nice against torpedoes. I may be mistaken on that account, but that's my interpretation of E-10.

Active sonars would be searchlight types with a narrow sound beam. Bad for search (ironically) but good for tracking contacts. Possibly they could be operated in a passive manner without echo-ranging, depending on receiver directionality. I would question their utility against a torpedo spread.

The US evaluators found Japanese hydrophones and sonars to be pretty modern and effective. Seems the big downfall was translating effectiveness into a coherent submarine tracking and attack system.

Do you know of instances where Japanese ships heard torpedoes during an attack? I am by no means denying it happened -- I just don't personally know of examples.

 

@Shaftoe I am sorry if I said something foolish or offensive. As E-10 says, Japanese hydrophones were stationary and the sonars had nonretractable domes. So the devices theoretically could be operated at any speed. But increasing noise at higher speeds likely would make this less feasible.

Edited March 23, 2020 by disc

[lordcmdr]

They would be useful especially if you ever do a submarine or carrier expansion.

[arkhangelsk]

On 3/24/2020 at 1:02 AM, disc said:

Do you know of instances where Japanese ships heard torpedoes during an attack? I am by no means denying it happened -- I just don't personally know of examples.

Unfortunately, I can't say I do, at least not clearly. The problem is that most sources don't seem very interested in going beyond "X was attacked by torpedoes. Y torpedoes hit (OR X evaded)." Unless you go through a War Diary that happens to go into details, you won't even know the contribution of hydrophones to Scharnhorst's ability to doge torps.