A complex for extraction of minerals on the seabed and as one of its most important elements - a single-stage axial hydraulic turbine - is considered. Its mechanical characteristics and geometric parameters, which determine the location of the middle lines of the blades in space, are calculated. It has been established that at increase of hydraulic turbine diameter from 0.5 to 1.2 m capacity increases by 89 %, and efficiency value by 11 % and takes the value of 84 %. Mathematical dependences are obtained which allow to determine the average diameter of the hydraulic turbine impeller at the pre-design stage. Designs of actuators for the development of polymetallic ores on the surface of the seabed are also proposed.
