Tores mailbox VIIC and VIIC/41 operation and technical details

[tore]

Q: Engine Room - Bilges

Tore, on plans for the engine of the Type VIIC

[NZSnowman]

Tore, I was thinking about the box keels, and how they would have rested on the sea floor. There seen to be no direct contact between them and the bottom of the keel to help with the load distributions.
 
I was wondering perhaps they were used to restrain that part of the boat while it was in dry-dock being constructed. I imagine that the two engines are very heavy and would put a large amount of stress on the framing around this area.
 
After the engines were installed and just before flooding the dock, they could not remove box keels, so build the keel around them and left them in place.

[tore]

Tore, I was thinking about the box keels, and how they would have rested on the sea floor. There seen to be no direct contact between them and the bottom of the keel to help with the load distributions.
 
I was wondering perhaps they were used to restrain that part of the boat while it was in dry-dock being constructed. I imagine that the two engines are very heavy and would put a large amount of stress on the framing around this area.
 
After the engines were installed and just before flooding the dock, they could not remove box keels, so build the keel around them and left them in place.

Simon
I`m not sure if I understand you correct, may be we are talking about two different things. You sure  have a crossection drawing of the boxkeel which goes all the way from frame 12 to frame 65. You would see it is a very strong thick steelboxshaped "beam"providing a very wide flat seating far wider than a normal ship. Inside the box are thick steelcrossplates placed exactly on the pressurehull where the inside frames are situated all along the flat restingplate on the keel apart from the area were the Kingstonvalves (Flutklappe) are. In addition to that I believe it was a longitudenal centreplate inside the box.This makes it possible to put the sub at the seabottom even when the seabed is a bit rough. When drydocking a normal ship you have to taylorplace wooden blocks so they are placed excactly under the frames for distribution of the stresses and every ship has a dockingplan for that. The sub carries its own foundation along and don`t need that thanks to the long superstrong boxkeel from frame 12 to 65. Another thing is that the sub has almost neutral boyancy hence the weigthstresses are small compared to that of a drydocking. The below picture is of Kaura in drydock resting almost entirely on the boxkeel but have wooden supports on those areas outside the keel illustrates perhaps the drydock question. Please come back if it`s still not clear.
Tore

[TopherVIIC]

That photo looks almost as if there is a torpedo in #3!

[tore]

That photo looks almost as if there is a torpedo in #3!

Christopher
No I dont`t think we had a torpedo in the tube. I think they were working on the inside and you see reflection from a lamp.
Tore

[TopherVIIC]

I know Tore - I was joking!

[tore]

I know Tore - I was joking!

As a Marine you should know not to joke about ammo that`s seriuos stuff.
Tore

[TopherVIIC]

I am entirely sure that the Norwegian Navy is competent enough to remove live ammunition from its tubes before throwing her up on dry-dock! Where else are the torpedomen going to nap during lunchtime? :-)

[tore]

I am entirely sure that the Norwegian Navy is competent enough to remove live ammunition from its tubes before throwing her up on dry-dock! Where else are the torpedomen going to nap during lunchtime? :-)

Right Christopher!
Tore

[tore]

Simon
I think I understand what you mean. I dont think the two red circled items on your drawing has anything to do with the engine mounting. There are in total 4 such to be seen in the boxkeel between frame 17 and 18,28 and 29 aft and then frame 37-38 and 54-55. The sub was built as described below.
I believe it is a possibility these were openings for the huge liftingstrap when the two pressurehull parts were joined at the slip.
The building of the VIICs was done in the following succession I believe. First the whole boxkeel was placed on a trolley at the slipway. Then the two prerolled curved pressure hull parts appr 125 tonnes each were hanging in a huge crane and joined by welding, followed by frames and smaller steelpieces all welded together, then it was launched and towed to the fittingout quay where the engines were lowered into the hull through pressurehullopenings above the engineroom which were closed by welding.
Tore

[TopherVIIC]

I had always wondered what those were also - your description makes it easy to picture its configuration through the box-keel. I just texted and showed the drawing to my sister who worked at one time for a company called Safety Sling, and she had her former engineers confirm that it was probable what they were for. They agree with you! :-)
Christopher

[tore]

I had always wondered what those were also - your description makes it easy to picture its configuration through the box-keel. I just texted and showed the drawing to my sister who worked at one time for a company called Safety Sling, and she had her former engineers confirm that it was probable what they were for. They agree with you! :-)
Christopher

Christopher
You certainly have your supportgroup stand by.
Tore

[TopherVIIC]

Christopher
You certainly have your supportgroup stand by.
Tore

Tore - I am just lucky she still has connections - she does not work for those folk any more, but is still on friendly terms. They just happen to provide tools for lifting very heavy industrial type things. :-)
Christopher

[tore]

Christopher
You certainly have your supportgroup stand by.
Tore

Tore - I am just lucky she still has connections - she does not work for those folk any more, but is still on friendly terms. They just happen to provide tools for lifting very heavy industrial type things. :-)
Christopher

In those days before the libertyships and sectionbuildings were common, heavy lifts of 100-150 tonnes were not done at every yard. The germans were pretty advanced  not only  technically but productionwise as well.
Tore

[NZSnowman]

Thanks, guys!