the sea is a nuclear submarine by a joint us and japan to allow the japanese to possess a nuclear submarine serving under the us 7th fleet but during the events shiro kaieda the sea bat's captain mutinied and attack other us nuclear subs without sinking them and declears the submarines independance and renames the sea bat to yamato turning it into an independant nation with shiro kaieda smuggling a single nuclear warhead to secure his nations independence
info about anime/live action
https://en.m.wikipedia.org/wiki/The_Silent_Service
YS Yamato Ex-USS Sea Bat
Sea Bat-class nuclear submarine
length 113.7m
beam 11m
hull hight 12m
weight 7500t (Submerged)
armament
x8 53.3cm torpedo launchers
x18 vls
cuising range infinite
maximum diving depth 1000m crush depth 1300m
hull titanium pressure hull 28cm