U-type Passive Roll Stabilization Tank

The studying for attempting to control and reduce the motions of a ship gets a lot of attention. Excessive motions interfere with the recreational activities and comfort of passengers. Passive Anti-roll Tank (PAT) is one of the important developments of stabilizers. This paper finds that U-tube passive anti-roll tank is the more economical stabilizer through analyzing many kinds of stabilizers.This paper analyses the forces acting on the ship-tank system by detail. According to anti-roll tank theory, the motion equations of PAT are obtained. The mechanism of tank damping and the calculation method of tank damping are analyzed. The effect of each parameter on anti-roll tank is studied. A design method of anti-roll tank is developed and each parameter of anti-roll tank can be decided by the method. The effect of ship characteristics after installing anti-roll tank is predicted. The roll motion of ship on irregular wave with or without anti-roll tank is predicted with spectral analysis method. The method is developed to software with Fortran and Visual C++ language on windows platform. The roll motions of two Ro/Ro ships are calculated and calculation results are in good agreement with the issued papers. And the calculation method is also tested compared with an actual ship experiment and the result is also satisfied.The method can be not only used in designing a new PAT , but also analyze the characteristics of a designed anti-roll tank.