Hi, I will refresh this quite old topic: on the site, the U-13 war diary from her second patrol was published: In this war diary, you can find many interesting information regarding the mining operation: -- Regards Maciek
Forum: Technology and Operations

Hi, try to upload images according to this instructions: Then, we will try to identify your item. -- Regards Maciek
Forum: General Discussions

Hi, all needed information you will find here: -- Regards Maciek
Forum: General Discussions

Hi, I can quote data from U 93 trials: | rpm | speed | current consumption (both motors) KF | 76 | 2 | 196 LF | 113 | 3 | 402 HF | 184 | 5 | 1334 GF | 275 | 7 | 1862 AK | 300 | 8 | 2996 In this document: at page 133 (in paragraph "Capacity, discharging, final voltage") you can find table with values of the discharge current and discharge rate for a single battery.
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Hi Onkel, for detailed information, look to this manual: pages 49-52. You can also look into this document: Radar impulses were heard in the headphones as a buzzing sound of frequency depending on the so called pulse recurrence frequency (or pulse repetition frequency), for WWII radars 200-600 Hz. Its loudness depended on the input signal strength (as you said). -- Regards
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Your second set of coordinates points the same place as your first set. Are you talking about this point? 10°09'12.7"S 51°03'06.7"E Regards Maciek
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Well, for me it looks like rocks. The Atoll was well researched and is visited by tourists, don't you think someone would spot the wreckage in the shallow water or even on the sand cay? Here you can see the document with maps of the Atoll: Here is the map from the above document, I marked the place, where the wreck would lay if it would be true. -- Regards Maciek
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Hi, try to start from here: -- Regards Maciek
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Hi, U 193 left Lorient for her last patrol on 23 April 1944. On 13th May was considered lost by BdU: "U 193 must be considered lost. Boat has not sent passage report after 21 days. Loss probably caused by air activity in Biscay area." So your accident can not refer to the U 193. -- Regards Maciek
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Hi, you can try here: or here: Regards Maciek
Forum: General Discussions

Hi, the type II, VII and IX U-Boats were not fitted with air-conditioning. Type XB and XIV as well as type XXI were equipped with such system. Some details you can find here: -- Regards Maciek
Forum: Technology and Operations

Hi, type IX U-Boats (as well as II and VII) were not fitted with air-conditioning. The air renewal system consisted only from CO2 absorbers, oxygen flasks for oxygen supplementing and air-fans for ventilating the boat. There were no means for lowering the air-temperature and humidity control. If you have any further questions, post them here, and will try to find answers. -- Rega
Forum: Technology and Operations

Hi Adam, I think you have to find the U-Boats which sailed out in the end of August (using BdU KTB ). Then you can try find their positions using this site: For some boats (ie U14, U18, U22) their positions were recorded. -- Regards Maciek
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Hi Nobby, "Abhorchen bei der UAG-Schall" Listening trials performed by UAG-Schall (Unterseeboote Abnahme Gruppe-Schall = U-boat Acceptance Group Schall). "Wechsel des Standsehrohres in der Holmwerft." The fixed-eye-level periscope (attack periscope) was replaced by the Holmwerft (in Danzig). -- Regards Maciek
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Hi Barbara, it seems, that he joined to the crew of the U299. For further information I suggest to contact with the Deutsche U-Boot Museum: -- Regards Maciek
Forum: General Discussions

Well, in the conning tower was a main rudder steering station. While cruising submerged, it was easier to communicate with helmsman, when the lower hatch was opened. If there was a submerged attack conducted, in the conning tower were also commander (at the periscope) and TDC operator. The commander wanted to have good contact with the L.I. below (in the control room), who controlled depth-ke
Forum: Technology and Operations

Hi, yes, you are right - there are two hatches. The hatch between the control room and conning tower is required for safety reasons. The conning tower - as the structure protruding above the hull, is exposed to damages from ramming (when boat is operating at periscope depth or near the surface). In such case, if conning tower structure would be damaged, there has to be way to isolate it fr
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They used so called stuffing boxes (Germ. Stopfbuchse). Example you can find here: You are absolute right about much greater differential pressure - some minor leaks were just assumed. The water from the leaks were accumulated in the bilges and from time to time had to be pumped out. The greater depth - the greater leakage. -- Regards Maciek
Forum: Technology and Operations

Well, it depends. If the serious leak is for instance in the aft compartments, then the safe is control room. If leak is in control room - safe are the forward or aft compartments. -- Regards Maciek
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Hi Paul, paul tjader Wrote: ------------------------------------------------------- > Could anyone of you clever people try to solve an > enigma.Uboat Feldpost M34354, or 50196, possible > Norwegian boat Kplt roughly 28 years old? The Feldpost Nummer 50196 belonged to the U639 (in 1.5.1942-19.10.1942). Info about this boat: and patrols: Indeed, it is Norwegian boat.
Forum: General Discussions

Hi, you have marked all bulkheads on type VIIC U-Boat. Bulkheads 1, 2, 3 and 7 are water-tight bulkheads. Bulkheads 4 and 6 are pressure-proof bulkheads. The data you are looking for are in the manual: Page 7: "Pressure-proof curved watertight bulkheads from the cupped side with internal pressure equivalent to water pressure at the top of the pressure hull 30 meters Pressur
Forum: Technology and Operations

Hi, markos88 Wrote: ------------------------------------------------------- > - Would the two boats run alongside at low speed > and use a highline with a pulley attached to > transfer supplies and (sometimes) personnel by > rubber raft? The food transfer as well as the canisters with distillate water were transfered that way. In the U459 KTB is also written, that after b
Forum: Technology and Operations

submarinehunt Wrote: ------------------------------------------------------- > Are these sight glasses the equivalent of the ones > we have discussed so far ? That's right. -- Regards Maciek
Forum: Technology and Operations

"V" stands for "Versuch" - "Trial/Test/Experiment" vessel. -- Regards Maciek
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SnakeDoc Wrote: > Well, I'm not sure, if perforated covers of gauge > glasses in the control > room of U995 are original, war-time equipment. If > you look on this picture > taken during the war: > > (U570 control room), you will see something like > steel cover, protecting > the glass only from one side (the side of the > glass opposite to the line
Forum: Technology and Operations

submarinehunt Wrote: ------------------------------------------------------- > Were the level gauges like an "open U tube" or > were they closed at one end .... i.e. behaving > like pressure gauges. I presume, that since the > scales are linear, they were open ended gauges ? They looked like this gauge for steam boiler: > Also, I wonder how did they see the l
Forum: Technology and Operations

submarinehunt Wrote: ------------------------------------------------------- > Just to make sure I have understood correctly, in > general use, the ballast tanks are either full or > empty. That's right. > The fine regulation of depth is by > adjusting the subs buoyancy, and this is done > using "regulation tanks". No, depth is controlled by means
Forum: Technology and Operations

submarinehunt Wrote: ------------------------------------------------------- > Are all the four scales showing trim tank levels ? For location of various tanks you can refer this drawing: -- Regards Maciek
Forum: Technology and Operations

submarinehunt Wrote: > Photo one: > > /in/datetaken-public/ > > Photo two: > > /in/datetaken-public/ > > In these images, I can see marked scales next to > perforated metal covers. > Next to these scales (2,3,5,8) I do not see any > liquid columns. Are these liquid columns under the > perforated metal covers to prevent injury if the >
Forum: Technology and Operations

Hi, with ballast tanks there is no problem - they should be only in two states: completely empty or completely flooded. Having them partially flooded (that means with air in the top part and water in the bottom part of the tank) was not intended and adverse - as the depth changed, the external pressure also changed, influencing the amount of water in the tanks (the deeper, the more water in
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