[Anton88]

There it is DivingDuck , I found it. -> U-615 (Kapitsky)

you'll like this..

DEPTH CHARGE PLOTTER:


In June 1943, a new instrument known as the "Wabe-Ortungs Gerät" (literally, "Depth Charge Locating Gear") was installed on the port side of the control room, just forward of the periscope motor and above the potato box. The visual part of the instrument was described as a bakelite panel about 30 cm. by 50 cm., attached directly to the pressure hull by metal brackets. On the panel was the outline of a U-boat surfacing at a


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sharp angle. Forward and aft of this U-boat were cruciform arrangements of small colored light bulbs, and amidships was a horizontal line of bulbs. It was stated that five bulbs were in each arm of the cross, and ten were in the horizontal line. The bulbs were spaced about 20 mm. apart. The bulbs to the left were red, to the right - green, above -- white, and below -- blue.

During an attack, lights flashing on the panel indicate the approximate position of the explosion of depth charges. The red lights indicate explosions to port, green -- to starboard, white -- above, and blue -- below.


It was stated that the instrument had a range of 500 meters. One prisoner was under the impression that when an explosion was located, it would be the policy of the captain to take the boat to the general area of the explosion, both on the theory that lightening never strikes twice in the same place, and as evasive action against echo-ranging.




Beneath the panel was a storage battery, placed on top of the potato box. The panel was covered at all times by a canvas cover except during an attack. The device was regarded as extremely secret and only could be served by the captain or the engineer officer.




When questioned about the Depth Charge Plotter, the Engineer Officer proved to be evasive, tricky, unreliable, and an unblushing liar. At first he denied the existence of such a device. When confronted by evidence to the contrary in his own note book, he stated that the instrument never functioned properly and that he regarded it as being only in its infancy. He said that the day after U-615 sailed, he discovered that several of the lights failed to function properly due to short circuits or faulty wiring. He felt that the sweating of the pressure hull might have caused some damage to the device. These statements are substantiated by




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an entry in his notebook which, in translation, reads as follows:


Depth Charge Plotter:


Shut off due to short circuit forward 13 June
Aft, below 1, 2, 5.
Aft, above 2.
Amidships port 5. forward (?) short circuit
Forward above 3.

(O.N.I. Note: The numbers probably refer to the various bulbs which were removed.)

On 14 June 1943, U-615 was attacked by an aircraft and the Depth Charge Plotter was tried out. The Engineer Officer kept a partial record of the lights which flashed. In translation it reads as follows:

Bombs at 55 meters (stated to refer to the depth of the U-boat)
Port forward 1; Port amidships 1; Port aft 1 and 2.

The last entry reads:

Three Depth Charges
Aft port 2.
Aft starboard 2.
Below starboard 2.
Forward port 1.
Forward (?) below 2.

"SEEHUND DREI"

It was stated by several prisoners that a special night telescope (Nachtfernrohr) was carried on the last patrol of U-615. It was said to have been used only by the captain and was in such secrecy that no very accurate description could be obtained. The instrument was brought



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aboard U-615 under armed guard shortly before she sailed on 12 June 1943. It was contained in a black case which was about 45 cm. long, 20 cm. high, and 10 cm. thick.

The prisoners knew of the instrument as "Seehund Drei". A radio rating described it as a stereotelescope with a strap and handles to enable the user to hold it in position. An electric wire connected the instrument to a power outlet on the bridge. He said that in general appearance, it resembled a field rangefinder.

Another prisoner, a seaman, gave a different description of the device. According to him, it was a single tube about 40 cm. long. On one end was a convex lens and on the other, the eye-piece. A leather handle enabled the operator to hold it in place. The electric wire, rubber insulated and about 1/2 inch in diameter, was said to go through the conning tower hatch to a connection below.

The prisoners had various ideas regarding the purpose of the "Seehund Drei". One said it was for observation of shipping at night. Another stated that it enabled the operator to see through fog. Still another had heard that it was used to spot aircraft at night. One stated that it operated with infra-red rays while another insisted that they were ultraviolet. One prisoner stated that it operated on 5,000 volts. When questioned more closely, he confessed that he wasn't sure whether it was 5,000 volts or 5,000 watts.

A radio petty officer from another U-boat stated that the original "Seehund" gear was a fairly old instrument, used on surface ships for visual signaling at night. He said that it was manufactured at the optical works of Leitz at Wotzlar and Zeiss at Jema. He described it as



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having a single tube with a pistol handle and trigger for sending. Attached to this was a binocular arrangement for receiving. He stated that an invisible light was employed in the gear. (O.N.I. Note: If this description is correct, it may indicate that "Seehund 3" is a development for another purpose, from an older signaling gear.)