Once upon a time a submariner named Leon Figurido created the insignia "DBF"... Diesel Boats Forever, and many fellow submariners were proud to wear it even after being passed to the shiny nukes of the modern "Rickover" era.
The US Barbel class while preserving a conventional machinery incorporated the hydrodynamic performances of an "Albacore" hull thanks to which she could reach a top speed just a little inferior to some of her contemporary nuke siblings.
I'm honoured to present you...: the Barbel!
Soon on the Cold Water's screens with DOT MOD Project's next release!