The effect of the liquid inside the Liquefied Natural Gas (LNG) tank on the ship's motion in waves is always a challenging topic in the seakeeping performance of LNG carriers. Further, the flow of liquid inside the LNG tank is perhaps a complicated problem due to its disorders movement. The focus of this study is investigating the effect of the LNG tank on the LNG carrier's motion and wave drift forces. In order to investigate the effect of the LNG tank, a model test in waves of LNG carrier was conducted in the wave tank at Changwon National University with and without the LNG tank. The potentiometer was used to measure the roll and pitch motion of the ship. Two load cells were attached between the ship bottom and the heave rod to measure the wave forces acting on the ship hull. Firstly, the pitch RAO and added resistance without the LNG tank are compared with the results from available researchers with the same ship type. Secondly, the motion responses of the ship in regular waves in various wave directions due to the effect of the LNG tank are presented. Thirdly, the wave drift forces due to the effect of the LNG tank are also investigated in various wave directions. Finally, the effect of the LNG tank on the LNG carrier's motion and wave drift forces was discussed.
The movement of the liquid inside the Liquefied Natural Gas (LNG) tank creates an extra force acting on the wall of the LNG tank. These extra forces may change the motion of the ship in waves, especially in roll and pitch motion. In addition, the movement of the liquid inside the LNG tank influent not only the motion of the ship but also change the 2nd wave drift forces. The influence of the movement of the liquid inside the LNG tank may place the ship in dangerous situations. Therefore, the ship's motion due to the effect of the LNG tank is necessary to investigate.
