Zwiebel and other hull openings

[uboatfan]

Hello togehter,

did anybody hav more information about the "Zwiebel" of U 889?
It seems not a post war modification.
What function?
Was U 889 the only boat with this?
See here: http://1.bp.blogspot.com/-sQ4I80oiH2s/UfPZnclaPJI/AAAAAAAAJ_U/jjIH48FiY8Y/s1600/U-889_zwiebel_3.jpg

Next question is about hull openings:
I do not exactly know the function of these openings. But it semms to be only on one side of the type IXC boats.
See here: http://2.bp.blogspot.com/-t5BKREOIQlI/UfQG_ODgdWI/AAAAAAAAKBQ/XxMiQoXQrCU/s1600/U-889_stern_2.JPG


On another picture i found a different structure:
https://farm8.staticflickr.com/7267/13245914154_94b5da9e69_b.jpg
On this page you see a square exhaust opening and two opening.
I found another picture with a trangle exhaust opening and three openings:
http://www.ebay.de/itm/Originales-Foto-photo-U-Boot-Lorient-1941-Trockendock-90-m-x-25-m-Foto-3-/141561422045?pt=Militaria&hash=item20f5b7e0dd

So what are they for?


Regaeds,

Uboatfan

[dougie47]

Hi uboatfan,
I don't have much info on the Zwiebel but according to Roessler in Die Sonalanlagen der Deutschen Unetrseeboote was also fitted to the Walter boat U 794. The XXII U 3003 is also mentioned so maybe it was fitted to that boat too. But I'm pretty sure no other IXs or VIICs had them other than U 889.
The hull openings on the stern of U 889. U 889 had a snort at that time so I am guessing it could be the exhaust outlet (when boats were fitted with the snort the exhaust outlet were moved below the waterline). U 858 had a very large outlet in this same location, though it was quite different to the openings on U 889. If this opening was not an diesel exhaust outlet, an alternative would be the outlet for Bold?
The square openings with two smaller sqaures below on the IX in 1940 at Lorient - I always thought these were the exhaust outlets. It is a bit similar to the outlet employed on VIICs in 1942, the exception being the two squares are lower down on the IX. But that is my guess - exhaust outlets.
Cheers,
Dougie

[NZSnowman]

Photo 1
Hydrophones. Only fixed to one Type IX, U-889.

Photo 2
Bold

Photo 3
I believe the square opening is not an exhaust opening but just a side casting hatch that is open. The two opening below the waterline will be the exhaust opening.

There was an evolution of exhaust opening during the war especially on the Type VIIC's. At the beginning of the war the Germans placed the exhaust opening above the waterline. As airpower became stronger during the war the Germans moved the exhaust opening below the waterline to hide the exhaust gases. As more boats started to use the snorkel device the exhaust opening was moved back to above the waterline.

Photo 4
I believe the triangle shape is square (and is an open side casting hatch). The two opening below the waterline will be the exhaust opening, third opening look to me as just being a wet patch on the pressure hull casting.

[OldNoob]

in photo number two
http://2.bp.blogspot.com/-t5BKREOIQlI/UfQG_ODgdWI/AAAAAAAAKBQ/XxMiQoXQrCU/s1600/U-889_stern_2.JPG

Not sure if those are some sort of fluted/louvered exhaust openings ?