Tores mailbox VIIC and VIIC/41 operation and technical details

[NZSnowman]

Tore, just noted a 2nd hot sea water line running aft to the air compressor but only from the starboard engine.

[tore]

Simon.
Coolingwater/ corrosion protection.
The Plate 13 shows a combination of systems. The warm water supply to the galley and washbasins are primarily served by the header tank in the tower getting its warm water from the mufflercooling, allthough there is a connection from the engineroom to the galley.
The piping you questioned is connected to the anti corrosion system. The Germans used an anticorrosion oil which emulsified with the coolingwater and thus protected the exposed steel/iron against seawatercorrosion. We never used it. The system works as shown on the system sketch below. You injected the  anticorrosion oil when the cooling watersystem was not in service. Every so so often a barrel of the oil was connected to the hoseconnection at the coolingwater handpump and pumped in to the coolingsystem by hand. By cocks and valves you are able to direct the the oilflow to each of the engines, the exhaustmanifolds and the Junker compressor. The other cooling systems in the aft torpedoroom were not incorporated. The anticorrosion oil for the engines (yellow) is pumped by hand to the main cooling waterchest (valve e is shut) and flows via valve e1 to valve f at the luboilcooler, out at valve d1 and through the engine in the normal coolingwater way. At the group exhaustvalve the main overboard seavalve is shut and the cock f1 is in the crossover position, leading the oil to the main aux. cooling waterpipe which has valve i 1 shut and the oil returns to cock g at the handpump, which is put in the hose/dirty oil drain position and leaves the system.
 When you want to treat the Junker compressor you shut the cock f1( engine coolingwater return via main aux pipe) and the oil flows to the aft torpedoroom (purple pipe) enters the compressor cooling system by open cock 6, (valve c and valve 5 shut,) through the compressor and leave via cock f to the main aux coolingwater pipe as return to the dirty oil hose connection at the handpump. This should explain you smaller pipes and crossover.
Appart from the anti corrosion mode, the main aux cooling pipe is of course used as an ordinary coolingwater pipe for emergency supply to the aft torpedoroom when needed.
Somehow the system would not accept the sketch at 380KB jpg I`ll post it separately.
Tore

[NZSnowman]

Tore, thanks for the information

If this pipe what is located on the shipyard drawing is for the Coolingwater/corrosion.

What is the pipe I previously thought was for the Coolingwater/corrosion that runs along the port pressure hull for?

[tore]

Simon.
Anticorrosion piping.
I understand your confusion, if you remember a few weeks back we were dealing with the cooling waterpipes fitted to the aft engineroom bulkhead I could not find a pipe which according to the system plate 13 should be connected to the anti corrosion pipe see picture below missing pipe marked red. That`s when I realized plate 13 doesn`t match with the u 995 system. I believe the 1943 and later boats had altered the old anti corrosion system possibly by introducing a special smaller pipe for the treatment.
So my assumption would be: the large pipe going aft at outboard port side is the aux. main coolingpipe from the aux coolingpump in the engineroom and the smaller pipe on the shipyarddrawing from 1943? is the modified pipe for the anticorrosion. The challenge would be to hook the new system to the aft torpedoroom Junker compressor.
Tore

[tore]

Simon
This thread does not accept my pictures anymore saying the download is full. I`ll e-mail you the picture.

Tore

[NZSnowman]

Cooling water/Corrosion

[tore]

Simon.
 Very good
Have you been able to find the connecting points ?
Tore

[tore]

Simon
The exhaust / inlet valve pedestal.
Having checked the photos once more I believe the most probable way of fixing the pedestal would be two bolts, the one inboard is obvious and the other most probably in the open area as shown on the sketch. In addition each pedestal has two location pins as can be seen on the photo. 
Tore

[NZSnowman]

Simon
The exhaust / inlet valve pedestal.
Having checked the photos once more I believe the most probable way of fixing the pedestal would be two bolts, the one inboard is obvious and the other most probably in the open area as shown on the sketch. In addition each pedestal has two location pins as can be seen on the photo. 
Tore

[NZSnowman]

Top: Cooling water/Corrosion System; Bottom: All

[tore]

Simon.
Not bad in spite of outdated system sketches. Apart for that, this system works better no wonder they changed the old .
 
Tore

[NZSnowman]

Tore, is this a access hatch?

[tore]

Simon.
Yes I guess it is the access  to the torsional vibration damper.
Tore

[NZSnowman]

Rocker Arms & torsional vibration damper cover

[tore]

Simon.
Torsional vibration damper.
The torsional vibration damper might be an unknown device. In all reciprocating engines torsional vibrations occur which might increase in value and eventually reach levels were the stresses can brake the crankshaft. In order to prevent vibrations to build up, a torsional vibration damper is installed mostly  on the front of the engine and is basically consisting of two masses (rings) spring or hydraulically connected and the uneven massvibrations created by the combustionforces are"chopped up".
There are a number of different designs, below is one not necessarily identical to the type installed on the GW engine.. In general they require little maintenance.
Tore