Abstract
Recent very strict regulations for the control of pollution in ports and waterways influence the stern tube sealing system. Conventional sealing system is based on the concept that lube oil pressure in the stern tube is kept always higher than sea water pressure, thus the propeller shaft and the stern tube bearing are not damaged when the seal is out of order because sea water ingress to the stern tube is prevented by lube oil pressure though lube oil leaks out. This concept is, however, no more rigid today.
The new type of sealing system is based on the idea that lube oil pressure in the stern tube is always lower than sea water pressure, whereby complete no oil leakage is achieved and sea water ingress into the stern tube is also checked step by step. The paper says features of the seal combined with the lube oil piping system and results of the laboratory test simulating possible various situations on the vessel.
