For the placing ship used in the waterway project, the setting of the best angle of the skateboard is an important index in the design process. A lot of construction is determined by the experience, but we can not judge the state under special conditions. After renovation of the “semi-submersible ship 1” , we get the friction coefficient range between the skateboard and interlocking pieces through many field tests, which is from 0.348 to 0.380. After setting the boundary conditions, we use the back calculation of friction coefficient and reverse engineering and obtain the skateboard best angle, i.e. 27.83° ~ 30.38°. Within this range, we can achieve the deck disposition of 2 m, realize smooth humping of skateboards when arranged in a single row of interlocking sheet, and obtain the best drum tension.