Awww, Fleischer just wanted...
...a chance to build another cool submarine set!
I'm rewatching 20,000 Leagues Under the Sea right now, for the first time since I was a kid in the early-70s, and when I came here to look at Richard Fleischer's other credits, I was suddenly struck by the similarities between the Nautilus and the Proteus (even the names are similar!):
• Domed windows
• If you painted the Proteus dark brown/gray and put rivets along the hull panels, it would look just as
'Steampunk" as the Nautilus.
• Similar airlocks