ASDIC clarification

[GoldenRivet]

WW2 era ASDIC pings

audible to the naked ear by crew aboard?

it is my understanding that the pings are in the ultrasonic range and thus would have been inaudible to the men aboard the u-boat meaning that every submarine movie and game has been wrong to make the pings audible for dramatic effect

however...

i am of the impression that the echo itself was audible and what the crew in the movies and games would actually be hearing is the sound of the ASDIC ping striking the hull so in this sense the movies and games were right to include these sounds.

does anyone have clarification or links to information... ive worn google out and not found much using my search terms

thanks

[Sailor Steve]

We've had this question before, but it's been awhile. U-boatmen have said that you could hear it, but it sounded more like gravel being thrown against the hull. Others said it sounded like the hull was being hit with a hammer.

Here are a couple of threads from awhile ago. The first one has an answer from you. The second one has some good links.
http://www.subsim.com/radioroom/show...ic+sonar+pings
http://www.subsim.com/radioroom/show...ic+sonar+pings

[GoldenRivet]

thanks steve... was having a discussion with someone and this came up, their indication was that nothing could be heard, period. i couldnt remember but i was sure there was something that could be heard and that surely i hadnt been wrong all this time

I think perhaps the red october scene where it sounds like the hull is being struck is probably most accurate.

[RustySubmarine]

As a ex submariner aboard an "O" Class Sub during the late sixties, you can definitely hear a sort of muffled sound, ( Similar to gravel or pebbles hitting the boat as Steve has mentioned). This depending if the attacking ship is within a certain range. You don't get a ping like the sonar operator hears. One thing I can definitely confirm, is that you do hear Mortar Bombs (these were fired from tubes on Anti Submarine Frigates) with a range of 600 yards. These live bombs fired in a spread pattern, (toned down versions were used on exercises), but were not powerful enough to cause any serious damage, but they did rattle things inside the boat and shake it about a bit, if they detonated close too. Quite an experience, but I'm glad I wasn't in one of the Uboats, where proper Depth Charges & Hedgehogs were used, these were certainly more lethal than the practice equivalents used in peace time.


Seems Iv'e reached the dizzy heights of an Engineer now,with 200 posts. That is what I was when I was in the RN. Petty Officer Engineering Mechanic.
Got a lot of catching up to Sailor Steve, with almost 44,000 posts. Is he The Admiral Of The Fleet?

[flag4]

Thanks for sharing that RustySubmarine.
It's great to hear about a first hand experience.

[Marcello]

Going by accounts of WW2 patrols of german and italians subs active sonar was audible by the crew as follow:
1) Ticking, as of a clock. Most common description I have encountered in my admittedly limited sample.
2) As if gravel was thrown on the hull.
3) Banging hammer (I have this replacing the stock ping in my game install).
Circular saw noises were frequently reported as well, but nobody was really sure if that was ASDIC or anti homing torpedo decoys.
Ping style sound is never described by those on the receiving end.

[Kelly621]

In twenty plus years of riding fast attacks and a couple of FBM's I never once heard any active sonar. Others on board did and described it similar to what has been already posted here, but being back aft by the propulsion equipment with ear plugs shoved in my ears I did not hear much of anything

Kelly621

[flag4]

*..off topic - a bit..*

I have a sonar ping for my ring tone on my android.



a bit like this but very clear -
I love it.

[Sailor Steve]

I've had one on my plain old cell phone for a couple of years now.

[nikimcbee]

On a side note, how did WW2 era sonar locate a sub on sitting on the bottom. Wouldn't the sub be lost in the return echo?

[ninja turtle]

Originally Posted by flag4

Thanks for sharing that RustySubmarine.
It's great to hear about a first hand experience.

[Tupolev]

I'm thinking it would be dependent on what the ocean floor was comprised of near the bottomed submarine.

If its rocks/reefs/sunken ships then I'd think the return echo would be split up amongst those features. But if its mud or sand the ping's energy might be absorbed by the ocean floor, leaving the highly reflective submarine highlighted.

But then I could be completely wrong.

[Mittelwaechter]

You are in search mode for an U-Boot reported or detected earlier...
A flat sea floor will show a constant line on your echograph. Suddenly the echo returns faster and you detect an object sitting down there. A few meters further the line stays constant as before.
You turn the vessel and pass over for a second time. Again you get that object scribbled on your graph. What would you do, Captain? I guess you'd tell your hydrophone guy to listen at this very special spot, but in the end you'd probably roll some ashcans overboard, just to make sure this structure receives a hit.

With a rocky seabed (big rocks, reefs and shelfs), it would be different. Your echograph could not differentiate between rocks and Uboat hulls, but it would be risky for a U-Boot to bottom down there...

[ArditoCorsaro]

My grandfather (chief machinist on board the submarine torricelli in june 40, red sea, war cross for gallantry in action, he was wounded too and passed 7 years in pow camps in india, after scuttled the boat.) was ambushes by an hunter killer group in june 40 in perim strait, after a couple of days of cat and mouse game, they was forced to gun action. Badly damaged the hms sorehan and the hms karthoum (the last sunked the day after for unclear reasons maybe for the damages. A shell from the italian sub hit her torpedo depot.) and later being hit scuttled the boat for avoid capture.
He told me that the noise he heard (they stilled 12-18 hours on the sea floor, damages, and chased, witg 45-50 degrees inside, in shadow.) during the hunt, was something like if someone was beating the hull, but a very light noise, not like a hammer, and later something like "pstchhhh".for a couple of secobds the beating, and so something like a "pstchhh" .
Also the italian escort sonar should have been similar. Because in alfa tau (a movie about the duel between hms triad and the submarine enrico toti) is very similar.
So he understood they was pinged.
The skipper passing in engine room, saw him was smiling, and asked: are you mad? But my old (18 years old, the most young of the crew) answered: no sorry captain, only is ironic that today it s my birthday and the enemy is bombing us.
Btw i guess there was diverse types of sonars. Some like if you throw sand on the hull, or an hammer noise, others like what we see in game. But someone sad me,(source: navyman) that when they launch 1 only ping, the sound was "piing" like we know, when they was contibuosly pinging, it seems that sand was throw against the hull. All could be guys.

[bstanko6]

The "mouse roar" was a
Known active sonar. Known for its high frequency. I
Would assume that sound traveling through dense fluid like water would be heard as a ping.

Then again, most subs today would never use it unless absolutely necessary. So I'm sure very few people know how they sound.