Time-based maintenance focuses on the periodic overhaul or replacement of motors, drive systems, transformers, components or its parts. In many cases however, these parts can last much longer than the manufacturer’s prescribed term. Especially in the offshore and dredging sector, where vessels are not always in continuous operation.

Cost savings for ship owners and operators

On the other hand, motors or parts can be worn out much faster due to experiencing heavier loads than previously expected. With condition-based maintenance, monitoring is based on visual inspections and electronic measurements. The collected data gives clear insights whether maintenance, overhaul or replacement is necessary. This allows the required maintenance to be executed at a more convenient time. In addition, the system is monitors equipment and is able to predict the occurrence of likely failures. Condition-based maintenance prevents unnecessary repairs and replacement if measurements show that maintenance can take place at a more convenient time. The main advantage of the new method is that the maintenance cycle can be optimized around the actual lifetime of equipment instead of pre-scheduled replacement.

“We see that many systems and parts wear much less quickly and last out longer than expected. With time-based maintenance, we replaced everything after a certain number of years, while our condition measurements now show that this is often not yet necessary,” says Arend van der Velde, head of technology and innovation at Bakker Sliedrecht. “These are essential parts of the whole power plant. The measurements give us a much better insight into the status and condition. That is why you see that condition-based maintenance is increasing in the market.”

Applicable in the maritime and industrial industry

Bakker Sliedrecht has already introduced and applied the new maintenance method to various dredging and offshore companies, as well as industrial partners. For the propulsion of some dredgers, for example, the bearings of generators and electric motors are monitored on the basis of condition-based maintenance. Also the Rotterdam World Gateway (RWG) container terminal on Maasvlakte 2 Bakker Sliedrecht uses this method to maintain the frequency inverters and circuit breakers of sixteen automated container handling cranes. “These cranes contain a large number of frequency drives. If you can postpone the replacement for two to three years with condition measurements, then you are talking about serious cost savings,” says Van der Velde.

Long-term efficiency benefits

Currently, service technicians use their laptops to collect and analyze data when performing condition measurements. The deviations and the fail values are immediately visible on the screen. Bakker Sliedrecht wants to be able to read this data remotely and further automate it in the future. “That depends on the method of data storage and the accessibility of vessels. To utilize the full potential of condition-based maintenance, solid cooperation with the client is very important,” explains Van der Velde.

By collecting and comparing the data from multiple assets, Bakker Sliedrecht will eventually be able to see whether processes on board are running efficiently and where they can be further improved. “Based on the observations from analyzed data, we can make recommendations to the client. For example, about a submersible pump that often runs up against the cavitation limit. We can then advise changing the drive speed. In this way, we hope to advise in more areas in the future to make ships operate more efficiently,” says Van der Velde.