T-Boss

This innovative solution replaces a vessel’s sterntube cooling tank with a dry,
irregularly shaped chamber (dry aft space) that allows for inspection and
maintenance of a seawater-lubricated single bearing and seal from the inside of
the ship, while the vessel is afloat, without having to withdraw the shaft in drydock.
This new design can better support simplified compliance with environmental focused regulations, such as the Energy Efficiency Design Index (EEDI) due to the
properties of the COMPAC seawater-lubricated bearing system. And it completely
eliminates the need for an oil-lubricated sterntube bearing and seal system – a
major source of marine pollution. The design can save shipowners hundreds of
thousands of dollars in capital and operational expenditure over a vessel’s lifespan.
Compared to a traditional sealed oil-lubricated shaft line, the T-BOSS concept
has the following changes:
• Sterntube is removed
• Forward Sterntube bearing and Aft seal is removed
• Propeller shaft line length can be now optimized, which can ultimately help to increase cargo space
•Aft Sterntube bearing is replaced with COMPAC seawater lubricated bearing with tapered key design
• Lubricant is seawater (no oil is used)
Recently, ABS granted Approval in Principle (AIP) to CSSC - Shanghai Merchant Ship Design & Research Institute
(SDARI) for the “sterntube-less ship” stating that the conceptual engineering as proposed is feasible for the intended
application. The AIP was based on the use of Thordon’s COMPAC seawater-lubricated single aft bearing

Thordon T-Boss Brochure