Objective: Review and analysis of engineering problems with the installation of a semisubmersible drilling rig in the set point of the water area and search of their decision. In article the platform construction is described. The analysis of external conditions of the area of installation and the restrictions defining working capacity and safety of operation of the semisubmersible drilling rig is made. Following the results of the analysis the task of determination of parameters of positioning system of the drilling rig and its optimization for the objective of expansion of range of external influences has been set that leads to increase in volume of the works performed during the season and economy of financial means. The method of the solution of an objective by mathematical modeling is offered.