Comments by "SeanBZA" (@SeanBZA) on "Drachinifel" channel.

Box is an electrical switch refurbishment kit, which while it is for the water distiller, those switches and parts would have been common throughout the U boat, so that kit would have been used all over, for switch and control maintenance, as the switches are a common ship part, and the ceramic parts used to contain the brass and silver contact blocks, and those do wear with use. That it was in the front was just that it was probably last used in the torpedo room as a tool kit, and then it stayed there, till it would be needed again for the water distillation plant, or there was more need for it at the front, or at least space to store it there, as often tools would be stored all round the ship, where you had a space free. BBC later on amalgamated with the Swedish Asea group, and then became Asea Brown Boveri, and later on also dropped the names, becoming ABB group. I have used Brown Boveri relays, they are an incredibly popular item in German built equipment, all the way through to this century, as they are both very reliable, and also very robust, with a lot of the relays going well past the rated million cycle guarantee, and some probably went well past the hundred million cycle point before they physically wore out.
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Will also add it can drive a lot of scanners directly, which improves the import process as it gets rid of the image conversion of the scanner software. If you are scanning use the highest resolution the scanner supports, and save as either a RAW image or as TIFF, not Jpeg which does a lot of compression on the image and thus reduces detail. Just remember that you can also add a description in the EXIF field as to image source and desription, though many online services strip this out as a matter of course. Otherwise you can make a text file with the same name as the image, containing the requisite details, which is saved with the image, though for a method that combines both look at making RAR images, which are a type that is first an image and then an archive of files that are all in a single file.
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Cordite and nitro also had to be manufactured cold, as they could otherwise detonate. A lot of modern explosives need chilled water baths during production, as otherwise they could self react and run away.
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@garywheeley5108 They likely carried at least 3 spare tubes for each position, and the same for light bulbs. However the bulbs and covers are almost always mounted with sturdy anti vibration mounts, so they do not really shatter as seen in the movies, they survive quite well, seeing as normally they have very sturdy heavy duty filaments, with a lot of supports. Submarine designers know there will be always water and vibration, so they make sure that things like lamps and the radios, along with all sensitive equipment and panels, are mounted on anti vibration mounts, which also serve a dual purpose to keep them from buckling as the hull is compressed at depth. Even the walkways and decks have the same anti vibration mounts, both to keep from transmitting noise to the hull, and to keep them from buckling. Damage from depth charges that breaks a bulb normally was pretty much followed by the hull breaching. Also the light fixtures all had at least 2 lamps in there, some having 4, 2 being filtered with a red glass, used in the conning tower so the captain could have night adapted eyes to use the periscope, or to run at night on the surface to charge batteries and change air. Submarines in that time were not well lit, which is why they had a lot of battery powered torches, to see to do maintenance and repairs. Those batteries were very carefully husbanded, though I would say a few enterprising submariners also managed to "acquire" lead acid mining lamps to use, as those are easy to charge off the ship batteries.
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@keithmoore5306 You use simple O ring and packing glands that are lubricated, so that the pressure the lubricated gland applies to the shaft is higher than the water pressure. Yes a much higher loss through the gland, but the alternative is to allow a small amount of water out to provide a boundary film, and use a scavenging pump in the bilge to pump it out at higher than ambient pressure. Alternatives are to use, for the rudder and vanes, hydraulic pressure, using high pressure hydraulic fluid pumped out through pass through fittings, that then drive an actuator that drives the rudder. That then just means your hydraulic cylinders need a simple boot on each end, so that you keep constant volume, filled with an inert fluid like hydraulic oil, so the actual shaft is protected from sea water. That fluid runs at a much higher pressure in the cylinder than the sea water at any depth it is rated for and they use a simple static pressure measurement to adjust the pump to keep the pressure high enough to operate, but not to blow the seals. Otherwise for hydraulics you simply make the working fluid water, derived from the internal fresh water supply, and use corrosion resistant material, but in all cases you need to compensate for the ambient pressure.
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@keithmoore5306 Yes the pressure varies, but the rudder operates on differential pressure, not absolute, though the modern ones use an electric motor outside the pressure hull, which solves most of the problems, though it does lead to needing to have the motor and reduction gearbox be filled with hydraulic oil, to keep it from imploding or getting water inside.
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@keithmoore5306 Prop shaft and periscope easy, the periscope has a top seal that is compressed down when it is down, sealing it tight against the gland, so it will not leak. Propshaft as I said they pressurise it with water to allow a lubricating film around it, and accept the extra friction of the seal packings, which are cooled as well by the water, and the RPM is kept low as well, because this reduces noise from the propellors. high torque so the extra loss is not too much compared to the power being transmitted through.
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@keithmoore5306 Yes I would not like to be in there, very cramped, and with the ocean pressure making that thick steel compress visibly as you descend.
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@keithmoore5306 Especially since that sort of info is still classed by the military as restricted, even on submarines that were last made a century ago, the derivatives are still in use now, and thus any info is definitely not out for public view. you would have to go to one of the exhibits and look carefully, and possibly ask the volunteers at the museums, but there they also might be limited as to info.
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Congratulations on the 100k, and while I think your work is great, I am not going to try for anything, give it to somebody else, like a school.
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Standard German design engineering. The big issue was they had a design for everything, and the US infantry got taught that if they saw field phone wiring how to tell US from German. US you took the wire, stripped off the insulation, and did a linesman splice on the bare wires, then let them fall back on the ground. The German fix was to use cast splice boxes, so the GI's were trained to take those splice boxes and break them, and cut the cable off to use to fix Allied cables. The German engineers also put in things like roller bearings for engines, and for gearboxes, while the US method was to put in sleeve bearings, and accept that they would only last 200 hours before overhaul, and for most engines it was not likely to last that long anyway, but you could fix in the field easily. Big difference in cost, and for sleeve bearing you are a lot less critical for dimensions, where roller bearings you need an entire factory just to make each part. Sleeve bearing all you need is a fire to melt the babbit material and pour into the cast, then a knife to shape it.
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