What do strut bearings support in a marine vessel?

Strut bearings are designed to support the ends of the shaft in a marine vessel. They play a crucial role in maintaining the alignment and stability of the shaft, which is necessary for the effective transfer of power from the engine to the propeller. By providing a stable support point, strut bearings help to minimize vibration and wear on the shaft, enhancing the operational efficiency and lifespan of the propulsion system. They ensure that the shaft can rotate smoothly, which is vital for the vessel's performance and maneuverability.

The other components mentioned in the options serve different functions in the vessel's structure and systems. While the hull's weight is primarily supported by the vessel's keel and frame, and the rudder system is typically supported by its own assembly, the specific role of strut bearings is concentrated on the shaft's support, making them integral to the marine propulsion system.