Condition monitoring provides key to ship automation

Modern ships have many systems – as well as those controlling the machinery there are cargo systems, communication systems, voyage planning and navigation – the list goes on. On the other hand, the greater complexity of ship systems is countered by desires to cut costs and reduce manning levels, without compromising efficiency or safety.

All of these pointers lead to one thing – a higher level of automation, across all ship systems. Wärtsilä has built a strong foundation for this in its application of condition based monitoring (CBM) systems for its engines. “Condition based monitoring is about knowledge of the particular installation, with maintenance decision based on real-time monitoring, leading to action being taken in due time before the need for down-time arises, ” says Jens Vägar, Manager CBM at Wärtsilä’s four-stroke centre in Vaasa, Finland. “In short, condition based monitoring helps optimise performance.”

Mr Vägar describes CBM as understand the process, analysis of data, then make predictions based on analysis and trends. The predictions, in turn, lead to formulating plans and schedules for maintenance, with cost predictions. Such plans are dynamic rather than governed by pre-determined schedules, allowing maintenance to be performed when it is actually needed rather then ‘just in case’, and coordinated with the ship’s operational schedule. The final element is a follow-up to confirm that the maintenance has been successful.

Wärtsilä has three CBM centres; Vaasa, looking after four-stroke engines in both marine and power plant applications; Winterthur in Switzerland for two-strokes, and the thruster centre in The Netherlands. Information from the sensors is sent to the centres at regular intervals, and compared with the data held on file for that installation. What levels are regarded as ‘normal’ will be determined by Wärtsilä’s engineers taking into account t the individual installation and expected conditions. Should any parameter go outside the normal range, or if a trend is noted that indicates a problem may be developing, this is noted, and the engineer considers whether action may be needed.

At agreed intervals, generally monthly, Wärtsilä sends a report to the customer, with any deviations from normal highlighted by a ‘traffic light’ system, where green signifies that all is OK, yellow showing that caution may be needed but there is no immediate risk of failure, and red indicating that maintenance action needs to be carried out or planned for the near future. The report will include the engineers’ recommendations. Interim reports will be sent if a critical point is noticed.

Exactly what level of attention the customer can expect depends on the type of CBM agreement in force. Wärtsilä operates four levels of service:

• parts supply, with fitting by Wärtsilä service personnel if required;
• technical management, which covers inspections, expert assistance and monthly reporting, exchange programme planning, and which can also include online condition monitoring, maintenance planning and full technical support and training;
• maintenance agreement with the customer’s own operating personnel backed by planned maintenance, including service crews from the Wärtsilä global network where and when needed; this level of service is generally provided on a fixed price basis, with performance guarantees.
• asset management, which is a comprehensive operation and maintenance agreement, tailored to individual customer requirements, but generally covering full operation, management and maintenance services, again with performance guarantees.

With CBM agreements in place for a figure approaching 400 installations, about 1,700 engines, Wärtsilä has built up a long experience of remote monitoring. Its first marine application was in 2002, on a Dutch dredger, and since then many other agreements have been implemented, the majority in the offshore and cruise sectors, but also including general cargo ships. The first marine installation to have a permanent 24/7 online connection to the Wärtsilä service centre was in 2007, on a drill ship operating in the North Sea oilfield.

The company has seen a steady increase in the number of installations. Up to now, most have been in land-based power plants, but the marine sector has been catching up, to the extent that it currently takes a 46% share, and Mr Vägar expects marine to overtake power very soon. With the growth of affordable satellite communication data links, about 70% of the marine installations now use an online connection, rising from about 30% previously. For some engines, such as the 50DF, an online CBM system is strongly recommended.

Although CBM itself is an established concept, said to avoid unplanned downtime, with some 90% accuracy, and increase availability by 20%, Wärtsilä sees its enhanced version of the system as a way of helping ship operators optimise performance and reduce costs still further. “Improvements in fuel consumption of up to 5% are perfectly achievable through using CPM to optimise the running of a propulsion plant,” says Mr Vägar. “This is on top of the well-known benefit of reduced maintenance costs – up to 20% with our system.”

The system makes it possible to optimise ship propulsion plant operation, making use of mathematical models for calculating the ideal operation parameters, and to dynamically compare actual with optimum values. The system takes into account variables such as ambient conditions, as well as installation-specific data including the engine specification, installation type and configuration, and design criteria. As well as optimising fuel consumption, it can be configured to reduce harmful exhaust emissions. Using measured values of parameters such as fuel pressure, charge air pressure and bearing temperatures, the engine operation can be optimised and a maintenance plan drawn up.

“CBM allows maintenance functions to be scheduled together; not all scheduled intervals, based on actual hours of operation, can coincide exactly,” says Mr Vägar.

So, the existing CBM system provides a basis for a more comprehensive, and more integrated, way of monitoring operation of the whole ship. This, Wärtsilä describes as the ‘Optimisers’ concept. Optimisers provides a platform to add different equipment, and link, through any type of communication link, to any application, located anywhere. So the sort of monitoring provided at Wärtsilä’s CBM centres can be used in conjunction with owners’ and operators’ own office-based systems, as well as third-party tools like ABB’s turbocharger analysis systems. “Instead of having 10 different monitoring systems, we would need just one, to monitor everything,” Mr Vägar explains.

One very important consideration in such an approach is security of data, and here Wärtsilä envisages the use of technology developed for military systems in hooking-up real-time connections. Easy optimisation and maintenance of the software is also essential, with no risk of obsolescence.

Mr Vägar says that another key issue is getting different types of systems, from different manufacturers, to communicate. He is confident that Wärtsilä can develop a suitable communication protocol that can be used by its partners; a major step in this direction has been achieved with the Wärtsilä 3C control system. This is described as “the first such system to fully integrate all significant data into a single platform to support decision making”.

The Wärtsilä 3C is at present a shipboard system rather than one intended for data exchange between ship and shore, but it should provide a platform suitable for expansion into remote operation. As a system designed for “fluent control of the vessel with priority given to situational awareness, safety, ergonomics and efficiency, which acts as a key enabler for the leveraging of energy management and integrated navigational solutions into a single powerful tool” it goes a long way to what the company expects to achieve with Optimisers. With 3C, advanced route planning is enabled through online data processing between the various systems, including ECDIS, voyage optimiser, econometer, power management, automation, weather chart, Navtex, and dynamic hull data.

The Optimisers system will collect data on site, store and analyse the data according to pre-set rules, and send the data to Wärtsilä for detailed analysis and complete reporting. The on-site system will be able to give simple reports and trending information to assist with instant decision-making, and users will have access to the Wärtsilä portal to access the detailed information and gain assistance.

Optimisers is seen as not just a product, but a complete remote integrated service solution achieved in collaboration with the customer and various partners, towards measurable goals. And the most important of these goals is optimising the total cost of ownership, not just through condition based maintenance but by fuel savings, voyage optimisation and other advantages.