1. Field of the Invention
The present invention relates to propeller-driven water craft and particularly to propeller shaft bearings of the same.
2. Description of the Prior Art
For propeller-driven water craft, a rotating propeller shaft is required, necessitating in turn a bearing system that diminishes frictive erosion about the shaft and its environment. The bearings take the shape of sleeves located along the length of the shaft between the mooring of the shaft located in the hull of the craft and the propeller located at the extreme of the shaft. The bearing sleeve may be fixed in place along the shaft either in the hull proximate the mooring or in a propeller support strut depending from the keel of the craft. In either case the prior art relies on such a bearing sleeve tightly fitted inside a fixed housing. Ordinary use of the craft will eventually wear the shaft bearing past its usable life, requiring the bearing's replacement.
Replacement of the prior art devices is a demanding task. The fixed position of the bearing housing and consequently the bearing itself makes removal of the shaft unavoidable if the bearing is to be accessed. In order to remove the shaft, which is in direct line with the rudder on a single propeller craft, the rudder assembly must first be removed, then the propeller, and finally the shaft. This procedure requires dry docking the craft. After the shaft is removed, the worn bearing must be manually driven out of place using a chisel and sledge hammer or, if this is not possible, burned out. The new bearing is then hammered into place and shaft, propeller and rudder replaced. The entire procedure requires several days in dry dock and several thousands of dollars in expenses.
Applicant is not aware of any prior art bearing system which eliminated the necessity of removing the shaft, the rudder, or placing the boat in dry dock.