The main reason for this phenomenon is that Morison equation is based on vertical cylinder model and supposes the infinitesimal section is completely immersed in water. Thus , the dis placement volume is considered as cylinder volume and the projected area of per unit length in the vertical direction of the flow are considered as the external diameter of the hose by default. However, the hoses are always floating on the sea under buoyancy whether they are in the state of transporting oil or not and only part of them are immersed in the sea. The displacement volume and the projected area of per unit length in the vertical direction of the flow is determined by the mechanical equilibrium in the vertical direction. obviously , the displacement volume is smaller than cylinder volume per unit length and the projected area of per unit length smaller than the default value. Hence , the wave load of floating hose in practical situation is smaller than the calculation based on Morison equation