That looks very good!
The interior looks like the CMK (?) kits. There are some sets frome one company available, for different parts and things.
One of my many ideas was the Typ-VIIC submarine in a small scale, (1/350 or so) and a dio for it.
But itīs not easy with the "water" and the other things. Perhaps a dry-dock would be an easy thing.
But I will see...
greetings...
Soeren