The German Hercules brand was a different company from the British brand. The bikes share very little in the way of design or components. The German models had the Thomson bottom brackets, Sachs Torpedo, Sachs, Perry, or Centrix rear hubs, and very different geometry.
I stumbled across a 50's German built Hercules tandem many years ago, it had 26x2.125" Semperit tires, a huge aluminum fender ornament, a springer front end that was made completely of stamped steel, and a stamped steel rear rack and full skirted rear fender. The bike was rough, too rough to restore but I tried to get it into some sort of working order. The wheels were spoked 36/40, with 10 ga. spokes, the handle bars and stems were brazed and not adjustable, the front bb shell had two bolts and a slot cut across the bottom, the internals were an odd double sided Thompson type rig which was held fast in the shell my means of tightening the two bolts and 'clamping the BB shell closed on the bearing cups. Since the front had two chainrings, the BB had to be double ended. The left crank and crank axle were one piece, there was no right front or left rear crank cotter.
The rear hub was branded Perry, but internally more resembled the smaller, more common Centrix hubs used in the 60's here.
The rear BB assembly was a reverse version of the more common Thomson BB but with standard threads on the right side. and a cottered crank and sprocket on the right side.
A lack of parts made me just give it a basic relube and a few new bearings and I sold it to someone more determined to make it 100% again, but I had never run across any other bike with that sort of bb set up again. It used standard 1/8" chain.
The bike was painted sort of an olive green, with black over white Hercules logos with ornate pinstriping. It had a flip down center stand, sprung padded leather Messinger, saddles, The frame was marked Nurnberg, Deutschland,
At the time I had that bike, there was no internet yet, so information on it was scarce, what little I found out about it was through contact with someone in Germany. When I sold it, I was extremely glad to see it leave, the bike was huge and took up a lot of space in the garage and due to its weight and poor condition, I had little interest in keeping it. It just looked like one of those endless projects that would never get done.