Hi Capt. Carl:

The torpedo aiming device, called the UZO (Unterseeboots Ziel Ortungsgerat) by the Germans, is mounted on a pedestal directly behind the forward sky periscope (control room / air search periscope). On a surface attack, some special 7 X 50 binoculars were mounted on top of this UZO computer transmitter and the targets were sighted though them. If the binoculars becamed fogged there is a set of open sights (like on a pistol) built of top of right tube of the binoculars.
The instrument that you see mounted fwd. on the rear periscope shear (attack periscope) is a Compass Repeater.
The following books have great illustrations of the conning tower or intrumention:
(1.)Vom original zum Modell: Uboottyp VII C: authors, Fritz Kohl &
Axel Niestle ISBN 3-7637-6002-4.(NOTE: This book is written
in German).
(2). The Type VII U-Boat (Anatomy of the ship No. 3): author, David
Westwood ISBN 0-87021-886-7.

Good Luck and Good Hunting,
Jerry Pope
DeSoto, Georgia