Tores mailbox VIIC and VIIC/41 operation and technical details

[Don Prince]

Hello Mr. Tore,


Did you ever have to use the port e-motor I as a welding convector?  Did you see the e-machinist set things up on the Rotary Switchboard on Kaura (U-995)?


Regards,
Don_

[tore]

Don.
In a way may be, but I would not say Q (neg. buoyancy) tank was regular ballast tank. As you know it was a help to speed up the first stage of diving than anything else.
Tore

Hello All,


It was stated that D2, D3, and D4 was the ballast system...  Could we include the Negative Buoyancy tanks in that category as well?


Regards,
Don_

[tore]

Hello Mr. Tore,


Did you ever have to use the port e-motor I as a welding convector?  Did you see the e-machinist set things up on the Rotary Switchboard on Kaura (U-995)?


Regards,
Don_

Don.
We did not have welding equipment onboard. I most probably have seen the first electrician working on the switchboard,but cannot remember the reason why.
Tore

[Don Prince]

Hello Mr. Tore,


The Lime Water Plate: 26 indicate valve (a), I assume 4 different valves are used to spray lime water on the batteries.  Is the spray above, below, or where?  Where does the Lime water come from?  Is it a pre-mixes solution that's taken onboard when taking on supplies at port, or is this something that was mixed as needed?


Regards,
Don_

[NZSnowman]

Hello Mr. Tore,


The Lime Water Plate: 26 indicate valve (a), I assume 4 different valves are used to spray lime water on the batteries.  Is the spray above, below, or where?  Where does the Lime water come from?  Is it a pre-mixes solution that's taken onboard when taking on supplies at port, or is this something that was mixed as needed?


Regards,
Don_

Don, I believe pre-Type VIIC/41 it was above, on the VIIC/41's they change it to below.

I also believe they added lime to a pipe opening in the Control Room and then run water through the lime and pipe.

[Don Prince]

Thanks Simon...


Regards,
Don_

[tore]

Don.
In addition to Simons answer, good to see you are still active Simon, I believe the limespray system is very much similar to the corrosionoil system, very seldom used and as such based on a hose connection system which could be hooked up to f.i. the hand coolingwaterpump in the engineroom. I don`t believe the lime was stored in liquid state on board, rather as a powder in canisters, which could be mixed with water. I cannot remember we carried any lime on board neither ever used the limespray. However once it was a narrow escape though. When surfacing in a bad weather a huge wave hit us at-wartship  just when our stability was at it`s worst,( metacentric hight almost 0) and we got a list, I remember looking at the inclinometer, between 35 and 40 degrees and that is a lot. Of course we checked the battery compartments but didn`t find any acidspill.
Tore 

[SnakeDoc]

Hi Gentlemen,

I believe the limespray system is very much similar to the corrosionoil system, very seldom used and as such based on a hose connection system which could be hooked up to f.i. the hand coolingwaterpump in the engineroom. I don`t believe the lime was stored in liquid state on board, rather as a powder in canisters, which could be mixed with water. I cannot remember we carried any lime on board neither ever used the limespray. However once it was a narrow escape though.

American report on type IXC U-Boat provides some further details:

Corrosion protection for battery wells from spilled electrolyte is provided by means of the so-called lime-milk system (Kalkmilchanlage).  This is merely a pipe fitted with a funnel or hose connection at the upper end, and with a perforated section or a bilge strainer at the lower end in each battery well.  By pouring milk of lime (slaked lime in water solution) into the upper end, an alkali to neutralize the battery acid is, in older vessels, sprayed onto the wing bulkheads of the battery wells from whence it finds its way to the bottom of the battery well.  On newer vessels the solution is delivered directly to the bottom of the battery wells.     
The solution is normally evacuated by way of the drain system.

Source: http://uboatarchive.net/DesignStudiesTypeIXC.htm

When surfacing in a bad weather a huge wave hit us at-wartship  just when our stability was at it`s worst,( metacentric hight almost 0) and we got a list, I remember looking at the inclinometer, between 35 and 40 degrees and that is a lot. Of course we checked the battery compartments but didn`t find any acidspill.

The cells of the battery could stand the trim changes up to 60 degrees and the heeling up to 45 degrees without acid spill.

--
Regards
Maciek

[Don Prince]

Hi Maciek,


They mix a solution of Lime and water... Where is the solution held, and how does it get introduced into a water system that sprays the walls of the battery room with the diluted lime water?


Regards,
Don_

[SnakeDoc]

Hi Don,

They mix a solution of Lime and water... Where is the solution held, and how does it get introduced into a water system that sprays the walls of the battery room with the diluted lime water?

I don't know nothing more than quoted above. I suppose (as Tore said), that they held kali powder in canisters or cans, and mixed with water in buckets when needed. Then, the solution was poured into the funnel in the upper part of the piping. Solution flowing through the piping, was distributed over the battery compartment through the holes in the pipe (maybe the spray is too strong word). I suppose, that the piping was led around the compartment along the walls, and the solution "sprayed" the walls.


--
Regards
Maciek

[tore]

Don.
In the unlikely event of acid spill, (having a pitch exceeding 60 degrees and list exceeding 45 degrees) most of the acid ends in the battery compartment bilges and you want to neutralize that prior to pumping the bilges by the bilgepump. As Maciek says I believe the lime granulate or powder can be solved in water in any container or bucket prior to be pumped by the handpump. The lime distributionpipe close to the batterycompartments bilges has a hoseconnection where you can connect a hose to the handpump discharge hoseconnection. You can see both connections on the piping plan.
Tore

[VIC20]

Tore, does it really take several minutes to fill the regulating tanks completely with water?


Are there any tanks that could not be blown with the diesels? (except those that could be pumped only)

[tore]

Mark.
I guess the filling time shall vary depending on how you fill them, by natural flooding the filling pressure surfaced varies between appr. 2 mWC. and 0, capacity of one reg. tank 7,6 m3. piping appr. 100 mm., if you fill with the main bilge and ballastpump you might have a filling capacity of 1,3m3/min against 15 m WC however restricted to a pipe diam of appr 100mm., the reserve fuel and reg. tanks 1 have a capacity each of 4.7 m3 and have of course a shorter filling time. Otherwise, submerged the filling pressure by natural flooding varies  with the depth. I never logged the time , but I guess with the above input you are able to estimate the time, remember the inboard venting pipe which might influence the head due to resistance in pipe and muffler.
Only the main ballasttanks 1, 2 and 4 port and stb.,3 and 5 are possible to blow by exhaust.
Tore

[Don Prince]

Hello Mr. Tore,


I have a few questions about Plate 21 Water...


Q1.  On the Skizzenbuch they list Hot Sea water --- I don't see a heating element to heat the water?
Q2.  Cold sea water is just plain sea water and not chilled?
Q3.  Below Waste Tank 1 they show a pipe connecting to the Washing Water Line...  Is this really true?  They crossed waste water with washing water???  I sure hope not!  Perhaps that line should have gone to the drain of that sink...


Regards,
Don_

[Don Prince]

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