Liquid cargo transport ship having double-hull structure

A liquid cargo transport ship comprising:

• a double-hull structure having bottom and alongside domains surrounding a plurality of cargo tanks for loading liquid cargo, wherein said bottom and alongside domains of said transport ship respectively consist of double-hull structure comprising a side plating and an internal hull plating;
• wherein a space domain formed between said side plating and said internal hull plating is utilized for a plurality of proper ballast tanks;
• and
• a plurality of tanks solely being available for ballasting purpose, wherein said plurality of tanks are provided at least partly in the domain of space inside of the plurality of cargo tanks disposed in the center domain of said hull structure along the fore-and-aft direction, at least one of said plurality of tanks solely being available for ballasting purpose and at least one of said plurality of proper ballast tanks being mutually interconnected with each other to form a single ballast tank.