I have been casually reading about U-Boat technology. Along with this excellent site, I have read [www.uboatarchive.net] about the Type VIIC the British captured in 1941, and many pages elsewhere.

But I have not found a clear explanation of the driveshafts of a VIIC, or any U-Boat. I found this line in the British report:

"15. Double cone engine and tail clutches are fitted."

I assume that this mean the VIIC was dual-propeller, dual-Diesel, dual-electric motor generator, with clutches both between the Diesel and the motor generator; and again between the m-g set and the prop; this repeated on each side.

Is this correct? Were there any reduction gears between the machines? How did the clutches close, manually or by air pressure?

Were all U-Boats Diesels and motors lined up in a similar manner? {Excluding the Walters series, of course..}


A second Diesel question: I read about the complex reversing gear needed to change the rotation of the Diesels. How often was this needed? I Ask because the electric motor was trivial to reverse, and if you need to reverse only at slow speed, such as when arriving/departing the dockside; could you not just use electric propulsion?