The present invention pertains to the field of water transport actuators, and it can be used for motion excitation of submarines, underwater robotic fishes, etc. The objective of the invention is to expand functionality and application fields of floating vehicle’s drive. Underwater floating vehicle is equipped with driving motors, motion converting mechanism and rotatable working heads. Device for driving force forming structurally is combined with the body of floating vehicle, which is made from three cylindrical parts with common longitudinal axis, besides these three parts are mutually kinematically connected and hermetically sealed. Front (1) and back (2) parts of the body are made as hard shells, but middle part (3) – as elastically flexible member. External cylindrical surfaces of front (1) and back (2) parts of the body are equipped with oppositely directed threads. Method to produce driving force in underwater floating vehicle includes the following operational procedures: i) rotations of front part (1) and back part (2) of vehicle’s body in mutually opposite directions about longitudinal axis are excited with the aid of driving motors (4); ii) to change motion path of floating vehicle, middle elastic part (3) of the body is bended in desired direction by cardan mechanism (7, 8) operating due to the signal of control system (6).