SONAR in the ship

[Milton]

Anybody have more information about SONAR in Bismarck???

As far I can remember from a British book about sonar developments in WWII, This ship was provided with a number of sonar detectors in each side that by varying the delay between the receiving elements (before summing -up all on one side together) provides this ship with an enhanced possibility of hearing underwater sounds, and also a steerable main lobe of sensitivity that permit the ship to be aware of other’s ships before making visual contact. (incidentally, this technology is used today in radars to electronically scan an area without the mechanical delays of moving the antenna).

But for me it is incredible that such and advanced technology exists at this time.

Any other info about sonar in Bismarck ????

[turlock]

I read of hydrophones in Prinz Eugen many years ago, but have never been able to confirm it. As for having them in Bismarck, I'd not heard of that, but it wouldn't surprise me. Tirpitz carried some "scare" depth charges. Actual SONAR in a Capital ship is not something I've ever read of.

[Tiornu]

Bismarck did not have active sonar, no. She had hydrophones of a very advanced type called GHG.

[bbisforbattleboat]

As far as I know, it was hydrophones, on both the Prinz and Bismarck (also Tirpitz). My impression is that the Prinz had more of them then the battleships. I assumed that this was sort of like pre-sonar, or the forerunner to it.

[tommy303]

SONAR and hydrophones are seperate technologies. The former is an active detection system using high frequency sound, the other is a passive listening device with directional capabilities. Hydrophones were developed in WW1 and SONAR came along in the interwar years. By the 1930s Germany had its own version of SONAR, called an S-Geraet, which was developed independently of British SONAR (ASDIC) research. The German GHG hyrophone arrays were highly developed and efficient, but like all hyrophones, was effected by sea state and ship speed. To the best of my knowledge, only escort vessels had the S-Geraet, although it appears that most large surface ships in the KM had the GHG as a passive early warning system.

[Ulrich Rudofsky]

The "sea state" influencing sensitivity and accuracy also included water quality like temperature, salinity, water depth, and suspended organic and inorganic materials. It has been said that GHG sometimes could not resolve reciprocal courses quickly and that it was very dependent on the training and intelligence of the operator.

[RF]

Bismarck did not have active sonar, no. She had hydrophones of a very advanced type called GHG.

According to Ludovic Kennedy the Prinz Eugen picked up the screws of Hood/POW at about 03.30 to 04.00 onwards on 24th May. Bismarck didn't pick them up. The report from PE evidently led Lutjens to think they were cruisers, and only learned otherwise when Hood/POW opened fire.

[Bgile]

PE's hydrophone operator reported torpedoes at the DS battle, causing the German ships to take radical evasion measures. There were of course none fired, and the evasion may have prevented further damage to PoW.

[RF]

PE's hydrophone operator reported torpedoes at the DS battle, causing the German ships to take radical evasion measures. There were of course none fired, and the evasion may have prevented further damage to PoW.

Could that report of torpedoes be caused by shell splashes close to POW?

[Bgile]

PE's hydrophone operator reported torpedoes at the DS battle, causing the German ships to take radical evasion measures. There were of course none fired, and the evasion may have prevented further damage to PoW.

Could that report of torpedoes be caused by shell splashes close to POW?

No. Torpedoes sound a bit like an electric drill. The point is the hydrophones were extremely prone to operator error, and ocean conditions can cause detection range to be very long or very short. You don't always know which it is. Who knows what they heard?

[Terje Langoy]

Hello...

I'm just curious. how was the hydrophones attached to the hull and where?

As for the detail of the detected torpedoes at DS, is it possible to hear anything in the water when you're aboard one of four ships in a heavy engagement? The guns alone make a lot of noise, but all those high-speed screws and shell splashes? How can you detect a single torpedo in that noise? I just can't figure it out...

How can you hear anything while sailing at almost thirty knots?

Regards

[RF]

Hello...



As for the detail of the detected torpedoes at DS, is it possible to hear anything in the water when you're aboard one of four ships in a heavy engagement? The guns alone make a lot of noise, but all those high-speed screws and shell splashes? How can you detect a single torpedo in that noise? I just can't figure it out...

How can you hear anything while sailing at almost thirty knots?

Regards

Interesting question. I presume that the operators gain experience over time and learn to differentiate between slight variations in sounds.

Allied destroyers were able to pick-up Axis subs while going at speed so it obviously works.

[Terje Langoy]

Hi, RF...

I apologise if this sounds stupid, but... I'm very fond of the movie "Das Boot" and would like to adress a particular detail in the movie that raise yet an interesting question, just since you mentioned the destroyer-use of sonars. In the movie, each time a destroyer closes in on U-96, you hear this kind of "Ping" getting more and more frequent as the distance closes. If I'm not mistaking, that sound give me a notion of an active sonar being used, not a passive listening device.

By the way, was the British ASDIC a passive or active sonar device?

Best Regards

[Bgile]

Interesting question. I presume that the operators gain experience over time and learn to differentiate between slight variations in sounds.

Allied destroyers were able to pick-up Axis subs while going at speed so it obviously works.

Destroyer hull mounted sonar is relatively useless at high speed. 5-10 kts is an effective speed. This was true in the 70s so I'm sure it was true in the 40s as well.

[tommy303]

Asidic was primarily an active sonar. Hydrophones were passive.