In the present paper, hydrodynamic behavior and bottom wetted surfaces of two-stepped planing hull are investigated by conducting towing tank tests. To this accomplishment, hydrodynamic resistance, reattachment length, trim angle, and bottom wetted surfaces are determined under different geometric variables of the two transverse steps and planing hull speeds. Qualitative investigation is also conducted on the forebody and aftbody wetted surfaces. Based on the obtained experimental data, lower hydrodynamic resistance is achieved by decreasing the aft step height at Fr_∇ < 2.12, while, greater aft step height is resulted to lower total resistance under Fr_∇ > 2.12. Reattachment length after the aft step is increased by an enhancement in aft step height and the longitudinal position of the aft step from transom. Moreover, aftbody wetted area after the aft step and total wetted areas are decreased by increasing the aft step height and decreasing the position of the aft step from transom. Also, an algorithm is suggested to calculate the forebody and aftbody wetted areas of two-stepped planing hulls.

本文通过进行拖船试验研究了两步滑行船体的水动力特性和底部湿润表面。为此，在两个横向台阶和滑行船体速度的不同几何变量下确定流体动力阻力，重新附着长度，纵倾角和底部湿润表面。还对前体和后体的润湿表面进行了定性研究。基于所获得的实验数据，降低流体动力学阻力是通过在星期五降低后台阶高度达到_∇ <2.12，而，大于后部台阶高度导致星期五下降低总电阻_∇> 2.12。通过增加后脚蹬高度和后脚蹬的纵向位置来增加后脚蹬后的重新连接长度。而且，通过增加尾部高度和从尾部减小尾部的位置，减少了尾部之后的尾部湿润面积和总湿润面积。另外，提出了一种算法来计算两步滑行船体的前体和后体润湿区域。