2008 Volume 43 Issue 2 Pages 258-264
The previous report described the corrosive wear on propeller shaft sleeves, made of bronze, in seawater-lubricated stem tube bearings. Accompanying is the occurrence of craters on the sleeve surface due to the action of erosion corrosion. As a countermeasure, based on the mechanism, this second report will provide the development of a catholic protection bearing, what prevents corrosion of the sleeve surface and reduces wear. Using anodes installed in some of the water channel grooves of the rubber bearings, this method is characterized by intermittent protection at best, and protection conditions were investigated by means of fundamental testing and using bearings of 140mm in diameter. As a result, a current density of 8A/m2 was found to protect the sleeve from corrosive wear. Cathodically protected bearings were also applied to bearings of 500mm in diameter and equipped for a ferry vessel. The results are presented here in terms of bearing design, trial running, and successful reduction of wear during actual in-service use.
