The significance of the stern shaft for ship navigation is mainly reflected in the following aspects:

Power transmission: The stern shaft is a key component in a ship's propulsion system. It connects the main engine and the propeller, transmitting the rotational power generated by the main engine to the propeller, enabling the propeller to rotate and generate thrust, thereby propelling the ship forward or backward.
Supporting the propeller: The stern bearing is subjected to various forces such as the torque, thrust and gravity of the propeller. At the same time, it supports the propeller through components such as the bearing, ensuring that the propeller can be stably installed at the stern of the hull and maintain the correct position and attitude during rotation.
Ensuring propulsion efficiency: The installation position and status of the stern shaft have a significant impact on the hydrodynamic performance of the vessel. A reasonable stern shaft installation can reduce the interference with water flow, avoid the reduction of propeller efficiency or the formation of cavitation due to water flow disorder, and thus ensure that the propeller can fully absorb the power of the main engine, improving the propulsion efficiency of the ship.
Ensuring ship safety: The sealing device of the stern shaft can prevent seawater from entering the interior of the hull, protecting the stern shaft and bearings from corrosion and wear, and avoiding the impact on the safety and stability of the ship due to seawater leakage. In addition, the strength and reliability of the stern shaft are directly related to the safety of the ship during navigation. If the stern shaft malfunctions, it may cause the ship to lose power and even lead to more serious accidents.
Reducing vibration and noise: Good stern shaft design and installation can effectively reduce the vibration and noise of the shafting. By rationally arranging bearings, adopting appropriate bearing types and ensuring the alignment accuracy of the shafting system, the vibration of the shafting system can be controlled at a relatively low level, thereby reducing damage to the hull structure and enhancing the comfort and concealment of the ship.