The present invention relates to a ship capable of natural circulation of
seawater by allowing
ballast water to flow in depending on the loading state of liquid cargo. In one embodiment of the present invention, a ship capable of natural circulation of
seawater is provided, which includes a cargo hold in which liquid cargo is loaded,
ballast water storage tanks arranged in a multi-layer structure around the cargo hold and storing
ballast water, a sea chest having a
seawater inlet and formed in the
hull to allow seawater to flow in, and a seawater inflow control device installed in the cargo hold and the ballast
water storage tank, which controls the opening and closing of the seawater inlet depending on the loading state of the liquid cargo, and allows or blocks the flow of seawater into the ballast
water storage tank by opening and closing the seawater inlet.