Incoming!

[Sailor Steve]

There has been talk on the SH4 boards about whether Japanese merchants had hydrophones, since some in real life did carry depth charges, and in that game they will suddenly start zig-zagging for no apparent reason.

Well, I just found out that some American merchants at least carried some form of passive device apparently referred to as a 'Torpedo Indicator'. A quick Google search turned up only active weapons indicators as used on warships for their own torpedoes, so I'm not sure how it works. I assume it's some form of passive omnidirectional hydrophone device that beeps or something when an incoming torpedo is detected. It doesn't seem to have worked particularly well in this case, but there it is.

At 00.08 hours on 2 Jul, 1943, the unescorted Bloody Marsh (Master Albert Harrison Barnes) was on her maiden voyage, when the ship´s torpedo indicator sounded after detecting the approach of a torpedo from U-66.
http://uboat.net/allies/merchants/2972.html

[Schroeder]

Interesting, I've never heared of such a thing (but what have I heared of anyway?:rotfl:).

[Kielhauler1961]

At 00.08 hours on 2 Jul, 1943, the unescorted Bloody Marsh (Master Albert Harrison Barnes) was on her maiden voyage, when the ship´s torpedo indicator sounded after detecting the approach of a torpedo from U-66.

Bejeeezus! It not only picks up the sound of the torpedo but it also knows the number of the boat that fired it as well???

Whats next? Your home mailing address?:nope:

[U-104]

:rotfl::rotfl:

[Sailor Steve]

At 00.08 hours on 2 Jul, 1943, the unescorted Bloody Marsh (Master Albert Harrison Barnes) was on her maiden voyage, when the ship´s torpedo indicator sounded after detecting the approach of a torpedo from U-66.

Bejeeezus! It not only picks up the sound of the torpedo but it also knows the number of the boat that fired it as well???

Whats next? Your home mailing address?:nope:
:rotfl:

"Skipper, we have an incoming torpedo! It's a G7A steam torpedo running a little slow at 41.3 knots, and the tube it was fired from is leaking. U-66 has made a left-hand turn and is watching us from periscope depth! The captain has just said..."

KABOOOOM!!!

[I-25]

LOL :rotfl:

[bigboywooly]

IIRC most Br battleships\cruiser also carried such devices
Will see if I can dig out my research

I expect that particular device was used by many battlewagons

There is a distinct diffeence to that though and the hydrophones some Jap ships are fitted with in SH4

[Mush Martin]

I imagine it listened for the common frequencies of highspeed
screws and wouldve likely had three hydrophones

I further would suppose that the display would not be
dissimilar to the depth charge direction display on later
US subs. ie. a circle of lights eight/sixteen? that represent
the circumference around the ship and the hydrophones
registering the highspeed sound would light the bulb on
the indicator in the appropriate quarter of the display

thats all a guess.
M

[GoldenRivet]

u-boats were equipped with such a device as well.

it was called "TAG".

It was installed in the control room of the XXI and was set to listen for pre-determined high pitched prop sounds, if one of these pre-programmed sounds was heard, a warning would sound in the u-boat would alert the crew.

I would imagine the allied system was very similar.

[Puster Bill]

u-boats were equipped with such a device as well.

it was called "TAG".

It was installed in the control room of the XXI and was set to listen for pre-determined high pitched prop sounds, if one of these pre-programmed sounds was heard, a warning would sound in the u-boat would alert the crew.

I would imagine the allied system was very similar.

That device is what I consider to be "proof" that the germans knew about the FIDO.

I find it hard to believe that a device that had a 25% success rate wasn't noticed by hydrophone operators, and then reported to BdU, by the boats that survived.

[U-104]

At 00.08 hours on 2 Jul, 1943, the unescorted Bloody Marsh (Master Albert Harrison Barnes) was on her maiden voyage, when the ship´s torpedo indicator sounded after detecting the approach of a torpedo from U-66.
Bejeeezus! It not only picks up the sound of the torpedo but it also knows the number of the boat that fired it as well???

Whats next? Your home mailing address?:nope: :rotfl:

"Skipper, we have an incoming torpedo! It's a G7A steam torpedo running a little slow at 41.3 knots, and the tube it was fired from is leaking. U-66 has made a left-hand turn and is watching us from periscope depth! The captain has just said..."

KABOOOOM!!!
:rotfl::rotfl::rotfl::rotfl:

[Jimbuna]

u-boats were equipped with such a device as well.

it was called "TAG".

It was installed in the control room of the XXI and was set to listen for pre-determined high pitched prop sounds, if one of these pre-programmed sounds was heard, a warning would sound in the u-boat would alert the crew.

I would imagine the allied system was very similar.

That device is what I consider to be "proof" that the germans knew about the FIDO.

I find it hard to believe that a device that had a 25% success rate wasn't noticed by hydrophone operators, and then reported to BdU, by the boats that survived.

A smal problem being that FIDO was generally used on boats that were in crash dive mode and probably not in the best position to be 'listening'

[Steeltrap]

Peter Cremer in U-333: The Story of a U-Boat Ace asserted the Germans knew nothing of FIDO until after the war. Given his operational experience plus posting at BdU, one would think he would know.