Why didn't they have towed sonar arrays?

[Quagmire]

A friend of mine and I were having a discussion on the capabilities of modern sonar (yes, sub freaks do this...) and the discussion turned to towed sonar arrays.

Question is, why didn't these exist in WWII? The technology is there to configure at least a primitive towed hydrophone. A simple hydrodynamic sled with a hydrophone on it that could be towed behind the sub so that you could listen while on the surface wouldnt be to hard to concieve.

And if they did exist, why didnt the Kreigsmarine develop one? If they can develop ladder running pattern torpedoes a towed array shouldnt be too hard?

[Hylander_1314]

IIRC, things like this were being developed later in the war, but did not make it to the application phase. Remember that sonar, and radar were both still in their infancy, just like ASW was. Just like "smart bombs" made their debut in March of 1945, but they were too late to be of any benefit to the flagging Luftwaffe. And it took nearly 50 years of technical advancements in electronics to make them practical.

[SteamWake]

Only thing I can think of is that nobody thought of it.

That and the fact that it was 1940 something and sonar let alone asdic were new concepts.

Also assetts were committed elsewhere especally on the axis side.

It would not supprise me at all if it had dabbled in. Hell they invented an airplane that could be launched from a sub (shrug).

[Stiebler]

There were a lot of complaints from U-boat crews later in the war about the amount of clutter with which they were having to contend while surfacing briefly under an Allied-controlled sky. Can you imagine trying to deploy such an array from a U-boat rocking on the surface every time you come up for air; half a dozen men on deck dragging the sonar array around in a storm, and at any moment the radar detector might begin its beeping.

If you have an automatic deployment apparatus from under the U-boat, what happens if/when it jams? The sonar array will register on asdic and create popping sounds underwater. It may also act as a drag on underwater speed.

Another potential problem: the sonar array, being towed, might easily wrap itself around the propellers. This was an occasional problem with early refuellings at sea from U-tankers.

Stiebler. (My guess, anyway).

[Letum]

I find it hard to believe someone didn't think of it.
There was stiff competition for resources and man power for thousands of new developments in the war. This one happened to be given a very low priority so it didn't enter planning.

Probably due to the lack of space aboard the U-boats! They would have rather stowed another torpedo back then. It was probably easier then to do a full 360 turn to hear what's behind them.

[Quagmire]

Yeah, you are proabaly right SubSerpent. German U-Boats were small indeed. I just was fondly remembering the towed array from my 688 Attack Sub days!

Actually the Germans did come up with a towed array of sorts. I am sure you have heard of the Bachstelze. A towed array for the air, not the sea.

Check it out:

http://uboat.net/technical/bachstelze.htm

http://www.flying-bike.demon.co.uk/helistuff/uboat.html

This would be a fun toy in SHIII wouldn't it! I don't know about losing a crewman every time I crash dive though. WAIT A MINUTE! That would be a great place to station seaman BERNARD!

[cobalt]

i dont think it would be practical because the diesels of the sub would probably drown out everything else in the ocean.

[Takeda Shingen]

Originally Posted by cobalt

i dont think it would be practical because the diesels of the sub would probably drown out everything else in the ocean.

You would have used it while submerged, not on the surface.

Ultimately, yes, sonar was in it's infancy in the Second World War. The dated hydrophone systems were little more than underwater direction finders where range had to be 'guesstimated' by the operator. This was not really a big problem for the operators due to the fact that, outside of the last few months of the war, submarines actually spent very little of their time submerged. It was the lessons learned regarding the danger of airpower that forced the submarine to be developed into a true sub-surface platform, rather than a submersible torpedo boat. As such, sonar would then become the primary, rather than secondary, method of detection and identification, which would push technology and development in a rapid fashion. The results were dramatic: In the course of nearly 30 years, ecompassing the First and Second World Wars, as well as the 1920's and 30's, the submarine remained virtually unchanged in regards to design and function. However, in less than 10 years following the end of the Second World War, the submarine would undergo radical transformations in both design and function.

[Hartmann]

The towed array in the ww2 could be useless.

the warfare sub against sub was nearly inexistent except for surface or periscope attacks,and the homing torpedoes where in the first stages of development.
and the enemy of the u-boat comes from the surface , the array listen below the surface and under termal layers .

also it adds drag in the submarine, perhaps reducing the speed.
is better shutdown the diesel engines and listen with standar hidrophones.

For the surface ships like the destroyers could be interesting but it takes time to deploy and makes impossible attacks runs with deph charges, with risk of blow up the sonar :rotfl:

[Cerberus]

There is another point which might make a WWII towed array less useful.

A single transducer towed on the end of a cable might be fairly sensitive because it's far away from the boat's own noise - but you wouldn't get any directional information from it.

To get more useful data, you need a series of tranducers spaced along the towed array & to do quite a bit of signal processing to combine the signals from each element in order to get directional information.

WWII electronics just wouldn't be up to that task. The result would be too big, too unreliable & too expensive*.
* in a wartime context - taking too many scarce resources.

[SteamWake]

Originally Posted by Cerberus

do quite a bit of signal processing to combine the signals from each element in order to get directional information.

and cancel out the "noise" of being dragged through the water.