Illustration of the strict tube design awarded ABS AIP.
ABS has granted its Approval in Principle (AiP) for a revolutionary vessel design with a novel aft structure designed to get rid of air pollution and promotes environment friendly vessel operations. It may also higher help compliance with EEXI and CII necessities.
The design has been developed by China’s Shanghai Merchant Ship Design and Research Institute (SDARI) in cooperation with Thordon Bearings Inc. and the National Technical University of Athens (NTUA). It takes a brand new strategy to the vessel’s aft structure that features elimination of the strict tube casting, using seawater for lubrication and creation of a chamber to allow in-water upkeep for the primary time.
These improvements allow shipyards and homeowners to get rid of shaft-bearing oil leaks, simplify upkeep and decrease prices.
Using seawater for lubrication of the strict tube bearing removes the danger of oil leakage. By enabling engineers and shipyard craftsmen to entry the strict tube with out the necessity for drydocking, the off-hire time incurred for bearing inspection and substitute will shrink from two weeks to someday whereas afloat.
The set up of an applicable torsional vibration damper may also get rid of the barred pace vary, which is current within the overwhelming majority of direct-drive diesel engine vessels. The new aft structure can thus higher help simplified compliance with environmental-focused laws, such because the Energy Efficiency Existing Ship Index (EEXI), and might allow extra environment friendly use of the engine’s propulsive energy as the entire RPM vary of speeds is obtainable for steady operation.
It allows homeowners to simply take into account an engine energy limitation (EPL) resolution if required, to adjust to Carbon Intensity Indicator (CII) energy output necessities.
The ensuing design proposal complies with all ABS guidelines and laws and the tail shaft survey will be maintained on the most 15-year interval if the ABS TCM-W Notation is adopted.
“The concept of using seawater as a lubricant is well-established and the proposed design takes this further by removing the stern tube casting, decreasing the shaft line length, reducing the engine room space and increasing the cargo space,” stated Dr. Chris Leontopoulos, director of the Global Ship Systems Center at ABS Athens. “The elimination of the Barred Speed Range and the creation of an aft chamber to enable in-water inspection, enable significant efficiencies and cost savings for operators,”
“Besides the benefits for operators, the new concept also gives more possibilities and flexibility for designers to optimize the engine room arrangement,” stated Wang Gangyi, chief engineer, SDARI. “Consequently, for shipbuilding, the initial cost including the construction materials and labor cost may be reduced accordingly. It will contribute a series of benefits to all parties involved with the vessel.”
“Our technical discussions have led to a revolutionary propeller shaft bearing system design that offers easy monitoring and maintenance of bearing and seal condition without shaft withdrawal, lower operational expenses and elimination of oil emissions forever,” stated Anthony Hamilton, Technical Director, Thordon Bearings, Canada.
