It would be possbile to do this but I think u won't find anyone who builds this for u
I would say u download an unrealism mod like:
'Killer Sub'
and u got ur advanced boat+4aft tubes
or u take for example the balao class and u tweak it with the minitweaker or Silent 3dtor to an higher underwaterspeed
the other way would be
-u cange the file extension of the XVIII from .upcge to upc
-u change the country( in roster files and upc)
-u need the senzori files, weapons and ammunition
-and u need time so that u understand the upc files
