Well here I go, First off, Anime Style SciFi is my favorite topic. The concept is based on Naval Ships with a Scifi twist.
I create a cylinder and extrude both ends to create a "boatish" hull shape. I always keep copies of my meshes and hide them just in case something goes wrong... I do a lot of Boolean cutting (Chopping an object with another object) and this can cause sudden failures. So keep this all in mind.