Suezmax Tankers Gain 660m³ Cargo Space With Single Design Tweak
A sterntubeless shaftline system cuts CAPEX and adds cargo capacity without lengthening the hull.
The comprehensive evaluation, based on a 274m (899ft) Suezmax tanker with a 670mm (26”) shaft diameter, demonstrates how the sterntubeless T-BOSS® system outperforms conventional oil-lubricated sterntube arrangements in multiple critical areas.
The study’s most striking revelation is the system’s ability to create up to 660m³ (23,308ft³) of additional cargo space by shortening the propeller shaft.
The economic benefits extend well beyond spatial advantages. The T-BOSS® system eliminates the need for sterntube lubricating oil, avoiding initial purchase costs of US$33,000 and generating annual operating savings of US$11,500. The polymer bearings used in the system also reduce shaftline drag, resulting in annual fuel savings of approximately US$5,100 for the reference vessel.
“A notable cost element is the expense of the sterntube lubricating oil purchase, which is eliminated with the adoption of the T-BOSS® seawater-lubricated solution,” the whitepaper states, highlighting one of the system’s most significant financial advantages.
How T-BOSS® transforms Suezmax tanker economics: With
The study’s comparative analysis across all shipbuilding disciplines reveals consistent cost reductions with the T-BOSS® system. Labour and installation costs are lower across the board, from sealing systems and piping to structural works and electrical systems.
The T-BOSS® system’s sterntubeless design offers operational benefits that extend throughout the vessel’s lifecycle. Its unique dry inspection chamber allows engineers to inspect and replace COMPAC bearings without withdrawing the propeller shaft or removing the propeller, keeping the vessel afloat and eliminating the need for costly drydocking. This feature significantly reduces downtime and maintenance expenses over the vessel’s operational life.
By removing the risk of oil pollution, the system minimises regulatory compliance costs and eliminates the need for expensive Environmentally Acceptable Lubricants (EALs). This makes compliance with strict IMO environmental regulations more straightforward and cost-effective.
The system’s design flexibility also enables naval architects to create more attractive and comfortable vessel designs. The study notes that T-BOSS® can “enhance layout flexibility at the early newbuild design stage,” offering shipowners and operators vessels with “distinct design wise, operational and lifetime economic benefits.”
Operational and environmental advantages of the T-BOSS® system
The collaborative development of the T-BOSS® system reflects the maritime industry’s commitment to innovation. Thordon Bearings partnered with Wärtsilä Shaft Line Solutions, CSSC – Shanghai Merchant Ship Design and Research Institute (SDARI), classification society ABS, and the National Technical University of Athens (NTUA) to create this advanced shaftline solution. The study itself was based on research conducted by Hydrus Engineering of Greece, supplemented by data from JBL Tech Service, ABS, and Thordon Bearings.
The combination of lower build costs, reduced complexity, greater design flexibility, and improved operational efficiency makes the system a compelling option for newbuild projects, particularly in the competitive Suezmax tanker segment.
The study’s findings come at a critical time for the maritime industry, as operators face increasing pressure to reduce emissions and improve efficiency. With the International Maritime Organization’s (IMO) greenhouse gas reduction targets becoming more stringent, technologies like T-BOSS® that offer both economic and environmental benefits are likely to play an increasingly important role in vessel design and construction.
As the industry continues to evolve, innovations that deliver tangible CAPEX and OPEX savings while supporting sustainability goals will be essential for maintaining competitiveness. The T-BOSS® system’s ability to address these multiple challenges simultaneously positions it as a key technology for the future of commercial shipping, particularly in the tanker sector where efficiency and environmental performance are critical differentiators.
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