Hi Mark,
In the torp room two racks of three torps ea. were aligned exactly with the two tuberows in front. Directly overhead were two rails each with a trolley and adjustable handy-billy. This rig would bring the torp abt. halfway into the tube. The other half was pulled in with a wire and pulley rig connected to a hydraulic piston under the floorboards. This way ea. torp was loaded from the top one down.
Do not know what the fractions of mins supposed to mean in Groener, but assume times acchieved in training. Since no XXI ever did a reload in combat condition (where it behooves one to be very quiet at the expens of speed), I think these times are somewhat academic.
The loading rack was replenished from the reserve racks P&S, with similar hydr. operated tackle bottom first to top. To pull a torp for servicing out of a tube, the rackspace directly behind had to be emptied first of the reload (reverse proceedure of above). Rgds, RB
PS: Franke not Henke. By late spring '44 Henke was POW, three months later dead. He did not see any XXI in operation.