This paper explores the hydraulic systems of modern steering gear devices. The Goal and Objectives were to explain how these systems work and why they are important, as well as how the SOLAS convention rules apply. The section Function and Classification of Steering Gear Devices describes the main types of steering gear devices. Basic Characteristics of Hydraulic Steering Gear Devices explains how these systems function and their advantages. Special focus is given to the Hydraulic Vane Steering Gear Device and the Hydraulic Piston Steering Gear Device, detailing their applications and operations. An important part of the paper is the Description of the Axial Piston Pump with Tilting Rotor, which is crucial for the operation of these systems. II Additionally, Auxiliary Components such as filters and safety valves are analyzed, highlighting their importance for safe system operation. In the sections Function of Hydraulic Fluid and Basic Properties of Hydraulic Fluids, the significance of hydraulic fluid and how its condition affects system performance are explained. The conclusion emphasizes that hydraulic systems of modern steering gear devices are essential for precise and reliable ship maneuvering. Proper maintenance and adherence to safety standards are necessary for their long-term operation.