In her original configuration berthing was not needed as she returned to HMB-1 every night. Later testing included longer duration operations and the berthing became needed.
Berthing is Navy standard for the era with 12 berths provided. A typical crew consisted of 8 standing crew operating the ship and 4 working the payload. However, on some missions as many as 24 were aboard and some where sleeping on cots in the payload space.
The crew usually worked "watch and watch", i.e. 6 hours on duty and six hours off.
Note the sliding indicator for Men/Women on the door to the head (bathroom/W.C.).
Through the door you can see across the passage to the Aux. Machinery Room.