Lokks like the exhaust was on the conning tower, according to this section of Blueprint there is something labeled "Dieselabluftmast" It's the bottom item listed in front of the periscopes, my German is really rusty but I believe that translates to "Diesel exhaust mast"
Hope this helps
__________________
GWX 3, JSGME 2.3, Sh3 Commander 3.2 SH3 Gen 8.1, Water Stream for U-boats, LRT LITE 2.0, Lifeboats for SH3