A recently formed alliance will look to create a new sustainability concept which could help cruise ships protect oceans from pollution.

Manufacturers Thordon Bearings and Wärtsilä have announced the formation of the Blue Ocean Alliance to develop and promote a new stern tube-less ship concept.

The stern tube in cruise ships is a hollow tube which accommodates the bearings, seal boxes and the propeller shaft. It is filled with oil, grease or water and forms a barrier between the water outside and the engine room inside the vessel.

The new concept, dubbed T-BOSS (Thordon-Blue Ocean Stern Space), involves a new ship design which does not require a stern tube and eliminates the need for oil-lubricated stern tube seals and bearings.

The design, the group said, is also likely to save ship owners “hundreds of thousands of dollars” in capital and operational expenditure over a vessel’s lifespan, including zero requirement for lubricating oil or biodegradable lubricants.

ABS, which has also joined the alliance, has estimated that in a stern tube-less ship design, a two-week dry-dock re-alignment or bearing and seal replacement job can be completed in a single day while the vessel is afloat.

New sustainability alliance brings together ‘formidable partnerships’

Ship designer SDARI, in partnership with Thordon and the National Technical University of Athens (NTUA), has already been granted an Approval in Principle (AIP) from ABS for the concept design of the stern tube-less vessel.

Thordon CEO Anna Galoni said: “The Blue Ocean Alliance brings together a formidable partnership to develop and further promote the concept. The fact that several ship owners have already shown interest in this solution is extremely encouraging.

“The T-BOSS concept introduces a new approach to a merchant vessel’s aft layout – removing the sterntube casing, employing seawater for lubrication and creating a dry chamber to permit in-water maintenance for the first time.”

Last month, cruise lines sprung to the defence of the sustainability merits of liquefied natural gas (LNG) after an environmental pressure group accused the industry of attempting to mislead consumers into believing the fuel source is a viable climate solution.