The present invention provides a floating marine structure. The floating marine structure comprises: a main body which floats on the sea and has a storage tank where liquid cargo is stored; and an offloading device which enables the offloading of the liquid cargo stored in the storage tank to a ship. The offloading device comprises: a cone-shaped submerged body which is to be docked to a cone structure of a submerged turret loading (STL) system formed in the ship; a cable which fixes the submerged buoy to be moored to a sea bottom; and a liquid cargo transfer line which connects the storage tank to the submerged buoy.
