HIGH LOADING CAUSES SEVERE MICROPITTING
The TSHD Shoalway is a trailing suction hopper dredger, owned and operated by Royal Boskalis Westminster.
A routine maintenance inspection revealed the presence of severe (micro)-pitting on the gear teeth of its forward and aft jet pump drives, likely caused by high loading. As a result, the Masson-Marine Type W4000 gearboxes had to be completely overhauled. This was after just 10,000 hours of operation.
Modern high performance, low emission marine diesel engines put increasing demands on their components. Top piston rings can be located higher, where proximity to the combustion chamber can increase the thermal stress. Higher fuel injector pressure and retarded timing improve control of emissions, but also increase engine temperatures and soot levels.
To combat these stresses and protect the engine, the highest performance lubricants are needed.
Benefits
Exceptional thermal and oxidation stability, antiwear properties
Outstanding performance at high and low temperatures
Lubricant analysis can reduce downtime by giving you data on the performance of your oil and equipment so you know when maintenance is needed
The PRODUCT
Synthetic lubricant and oil analysis service
ExxonMobil recommended switching the Shoalway to Mobilgard 1™ SHC, a high-performance fully-synthetic oil.
Mobilgard 1 SHC’s unsurpassed performance capabilities are the result of extensive cooperative development with major equipment builders. It is especially effective in extreme temperature applications, providing stronger lubrication film strength than most SAE 50 oils - despite being a SAE 40 grade lubricant.
To prevent development of similar issues elsewhere, the Causeway hopper-dredger also converted to Mobilgard 1 SHC.
To monitor the performance of the oil, Boskalis also followed ExxonMobil’s recommendation and implemented its Mobil Serv℠ Lubricant Analysis service.
The IMPACT
A significant reduction in unscheduled downtime
More than 40 months after the switch to Mobilgard 1 SHC, a visual inspection revealed negligible (micro) pitting and wear rates on the gears of the vessels’ pump drives. Meanwhile, used oil analysis indicated minimal formation of harmful deposits.
As a result, it was not considered necessary to overhaul the gearboxes again. This provided Boskalis with a substantial reduction in maintenance costs and unscheduled downtime.