Thanks guys. And yes, it's Santa himself on the bridge
It's definitely cramped but too small... I'm not sure since its size is roughly same in our current Tornio-class with same kind of equipment. Conventional and stretched bow would make it different vessel:
I tried to improve stability by adding retractable fin (and camo attempt...). However, I'm not sure is it any good in vessel this size?
But now something more cramped
A Minisub with four tubes able to carry torpedoes and mines. Crew of 8 + 6 divers, endurance 2 weeks, range 2500 nmi, speed 15kt; perhaps?