Feature 1 | DANISH MARINE INDUSTRIES
machinery, so that it could be applied to the ferry’s azimuthing thrusters, which are more complex and costly to repair than ordinary shaſt-propellers. Te system offers advanced warnings of
potentially expensive damages and is set up to avoid the loss of direct repair costs and indirect costs due to non-availability of a vessel at peak traffic times. It aims to reduce unplanned overhauls by 30%, potentially saving €1m- €.2m per year. Te online monitoring solution gives
insight into the actual condition of the thrusters, providing upfront knowledge about developing problems and the possibility to inspect and plan any repairs at an early stage, and to make the necessary repairs when it is least inconvenient. Te system’s patented AutoDiagnosis
feature provides automatic fault identification, issuing reliable warnings and predicting lead times to inspection. In the autumn of 2007, Hapag-Lloyd
installed the OPENpredictor condition monitoring solution on three 4000TEU containerships in service since 2002 - Dublin Express, Glasgow Express and Liverpool Express. Te systems monitor both the vessels 9-cylinder Wärtsilä engines and their Napier turbochargers. Te bearing wear monitoring solution from Rovsing Dynamics enables the crew to plan corrective actions in due time and offers many expansion options like monitoring of other machinery and integration of predictive maintenance information with other systems. Within six months, the investment
paid off, when OPENpredictor detected increased vibration levels in one of the turbochargers onboard Glasgow Express.
Te warning was given in due time for the crew to replace the turbocharger’s turbine rotor, thereby avoiding the risk of significant damage. Following the successful field
test on the three vessels in service, Hapag-Lloyd decided to equip its six new 8750TEU containerships under construction with the OPENpredictor online condition monitoring solution to cover the 12-cylinder MAN B&W main engines, with a view to saving time, cost and manpower by avoiding open-up inspections. Again, JSC Primorsk Shipping
Company recently selected Rovsing Dynamics to supply bearing wear monitoring of the MAN B&W engines for its new Ice Class, 104,000dwt tanker Zaliv Amurskiy. Seven sisterships will also now be equipped with the system. According to PRISCO technical director Konstantin Globenko, one of the speakers at Rovsing Dynamics’ vessel condition monitoring seminar at SMM in Hamburg last autumn: “Te main engine is critical for our tanker operations, so we want to make sure that it works around the-clock without problems. We are also looking to change our maintenance strategy to condition-based maintenance to avoid open-up inspections. Tese are critical for our operations, and we have experienced problems due to crew or shiprepair yard mistakes during inspections.” PRISCO intends to integrate
information from the monitoring system into its maintenance system DANAOS. “We want to have all data in one global system for control of vessel condition and condition-based maintenance planning,” Mr Globenko said.
MAN Diesel now recommends that
shipowners avoid regular open-up inspections of crank-train bearings when it comes to certain engine types, and that they only conduct condition- based maintenance, supported by various types of monitoring. Te overall aim is to increase vessel reliability and reduce operational costs. Citing ‘the human factor’, the engine
builder suggests that open-ups identify less than one percent of problems, while generating more than two percent of damages. Grave examples of open-up induced engine damages include forgotten tools inside the engine. Other damages include lube oil being contaminated with water, white metal or other foreign particles, thin/thick shell fatigue and steel-to-steel contact. In many cases traditional systems like oil temperature measurement and oil mist detection warn far too late, when bearing damage had occurred, or not at all. MAN Diesel identifies the monitoring
of bearing wear, water in oil, bearing temperature, shaſt line earthing device effectiveness as the ideal basis for carrying out condition-based maintenance. Rovsing Dynamics is one of MAN
Diesel’s approved vendors of bearing wear monitoring. If required, data on water in oil, bearing temperature and shaſt line earthing can also be integrated in the Rovsing Dynamics bearing wear monitoring system. Since Rovsing Dynamics launched its
first condition monitoring solution for maritime use in 2004, OPENpredictor has been chosen for more than 50 vessels, involving more than 12 shipowners, as a stand alone or combined solution. NA
The OPENpredictor graph shows how the turbocharger’s vibration level increased beyond the yellow alert level and the red alarm level on a Hapag-Lloyd vessel. The investment in the monitoring system paid off in six months.
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The Naval Architect April 2009
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