How did U-boats enter and exit the submarine pens at Brest?

How did U-boats enter and exit the submarine pens at Brest?

I was reading about the Brest submarine pen/bunker complex and looking at pictures of it. I was even able to locate a set of blueprints of the base here. But because of the poor quality of the image though I am unable to discern details on which way the submarines are facing in the dock, but it looks like they are backed in.

What I am unable to locate an answer to is how did the U-boats enter and exit the submarine pen. Did they use tug boats or harbor pilots, or did they back in so they could quickly get out if they were attacked or did they go in facing forwards?

I have checked all of the usual sources such as wikipedia on uboats, Brest, and submarine pens, in addition to finding the above linked source and several other ww2 historical sites, but none with this answer.


Watch the video: Battlefield S6E3 - The War Against the U-boats