modern ships in one piece(nihonkoku shoukan style-ish)

1.1. how

Ok so to formally start this story i need to ask for a good back story, since as can be seen by the previous attempt (which i deleted by the way), my skills at making a back story are as you can say "in need of extensive improvement", so I'm gonna need some ideas for a backstory, ill give credit where it is due, but i need help for this