Abstract
Since the oil-lubricated stern tube system was applied on the first Japanese ship in 1964, the oil seal type of sealings have been commonly used up to date. From the point of the prevention of oil pollution, the sealings have been improved according to the severe demand of reliability. That is, the rubber material of seal rings have been converted from Buna-N (NBR) to special fluoric rubber (FKM) and applied for smaller ships. On the other hand, the sealing structure is compact, and recently the aft sealings of four lips with a spare seal ring mainly tends to be adopted in order to get higher reliability on the prevention of oil leakage. Therefore, the sealing structure of four lips type and the rubber material developed recently are generalized, reported herein.
