Condition Based Maintenance to optimize Asset efficiency

Gerald Rofle, Manager – Marine Service Development, SKF Industrial Market, Marine  presentation during the 2015 GREEN4SEA Forum

Most people in the industrial world know the name SKF. It is a fairly big and well-known company. From a business model, in the marine industry and in many other industries, you make an investment. You decide to build some new ships, make a capital investment and spread the cost over 20 years or more. Then, when you put the ships into operation, you start paying the operating costs, which may vary depending on the vessel efficiency etc. And then, you go to work earning revenue. The idea is you get a payback point and you make money. And, I think the Greek community is very good to make money from marine for many years.

Unfortunately, unexpected things happen. Critical systems may fail, important equipment may have an issue and we experience unplanned downtime events, even resulting in off hire for the ship in the worst case scenario. I think we have all seen very big show-stopper events like this that occur occasionally, but thankfully, not very commonly, but they do happen. When unplanned events occur, you will incur an increased cost to repair the function of the ship or the system. Or you have to replace the ship with another ship to complete the contract. As a consequence, the original business model changes, and the payback point shifts, to a point where in fact you may or may not be making any money.

So, as you can see, effective maintenance and technical operations are extremely important to ensure the overall operational efficiency of the ship. We know that around 10-15 % of the total operational costs of the ship are directly influenced by the maintenance repair and overhaul activity, as well as having an indirect effect on consumable costs, like spare parts and labour.

I would say here, one of the main defence is to adopt a condition based maintenance (CBM) strategy, where the main objectives are to reach zero unplanned maintenance events, and gain an early warning of developing equipment faults, allowing you to fix them before you incur major consequential losses to the business. A simple analogy is that with a CBM approach you will only need to replace the bearing, not the gearbox. Condition based maintenance can reduce consequential losses again in the region of around 10-15%, and focus your resources on proactive activities related directly to asset efficiency.

In practise, if we consider the approx. 107,000 Classed ships in the world fleet, we see that the vast majority of the marine industry is today still working in a very prescriptive maintenance regime, under either a Continuous Survey or Machinery Renewal survey arrangement. This five year Class inspection cycle has been established for good safety reasons and to make sure you are running effective vessels. But, in practise, it probably results in too much maintenance on board, and too much intervention on machines that are actually working well.

Currently, we see more fleet managers are seeking PMS notation, to gain a more controlled inspection environment, but very few companies have a class approved CM program, because it takes some time and effort to achieve, as it requires very good discipline on board and very good processes. However, we know that around 10-15% of ship owners and managers are actually using condition monitoring as a basic diagnostic tool, but they haven’t a class approved process yet.

Progressively, we see the trend within Fleet managers is improving and that is why SKF are in the marine business providing such CBM services. When we look wider across the world of marine, we see major OEM’s, particularly main engine and propulsion system manufacturers, are also starting to offer to integrate condition monitoring (CM) into their new products, which is a positive trend which we encourage and support.

Also, for shipyards, we see some of them are also starting to get into CM, but we still see a major gap in shipyard knowledge of condition monitoring technology, and how to apply it correctly. Beyond the warranty period, it is the fleet owners and operators who experience the real pain of equipment failures, and this is where we see the driving force on the development of CBM within the industry. So, in our view, it is the end-user, the owner or operator, who should drive the future specifications of CM systems to be used on board.

Condition-based maintenance is not a technology – that is Condition Monitoring, which is basically the use of non-destructive testing by various means. Condition based maintenance is a Process, a deliberate maintenance strategy. So you have to start by understanding what you need to measure, which machines, how often, and why. Many people start with the wrong end. They buy CM technology and then try to apply it and it doesn’t actually give them the results they want, because they measure the wrong things at the wrong time, often in the wrong way.

When you design a new CBM Strategy in the right way, it will not replace all planned maintenance, although it may supplement the existing planned maintenance and replace some of it. Once you have the Strategy part right, then you can design a system for routine data collection, using portable systems or online technology. In addition, we see that remote analysis is now becoming very popular, because of increasing communications bandwidth, but today we still need to be able to transmit data to and from ships in low bandwidth environment. Thus, we work typically in the range of 120 to 200 kilobytes/second bandwidth. We do not expect to have megabyte size communication lines to do this kind of work, as it is not practically available, and is also expensive.

When we look at the overall CBM process, starting with the Strategy, System set-up, Data Collection, and Remote Analysis, then up to that fourth point, you have just spent money. When you reach the fifth point of Corrective Actions, and sixth point of Reliability Improvement, you actually start seeing the real benefits. You will then know how to make the right corrective actions and make well-planned maintenance interventions and, in the longer term, to learn to maintain and improve in a better way.

I’ll give you a couple of examples. The first major problem is that people face with a lot of vendors selling kit technology. Some of them are very good, some of them are less good, but it is a confusing sales environment. Should I use a Portable CM instrument or Online CM technology? Should I do vibration, thermography or oil analysis? All these may seem difficult decisions to take on intellectually and cost wise. Also, the marine industry has particular drivers like the crew is changing regularly, so how can we perform this sort of work on board? This is one reason why remote monitoring has become much more popular, to minimise the skill requirement on board. Also, for example, Grease and Oil analysis are commonly applied to monitor fuel oil and lube oil condition, but may also be used to check machine condition, so all these methods need to be applied in different ways. Fortunately, SKF manufacture and supply all of the main CM technologies, so we like to think we can give an independent view of what it is correct for the application.

Again, the CBM Strategy is used to define the schedule required to monitor each machine type. This is based on the equipment criticality, failure mode and likely rate of failure. This allows us to monitor auxiliary machinery with low failure rates on a periodic basis, usually three or four times a year, maybe up to six times a year. Where we have higher criticality and faster modes of failure, such as Propulsion Thrusters, we may need to use online systems, especially for equipment with variable speed, variable load operating conditions, which are difficult to monitor, and therefore need more intelligent systems. Finally, we see Protection systems used mainly in the naval sector, to protect high speed gas turbine equipment, etc.

The other thing that is developing and is now here in the world of marine is internet based monitoring, where we are moving things into the cloud. Also coming into marine are tablet based devices, cloud-based information systems, so we have to be ready for that. That’s the next generation. We are testing new Cloud systems currently with fleet managers, which will move all existing CM Software off the ship and puts it into the cloud, and puts the database in the cloud. This is a very good move, as it improves the data quality and overall cost of the program, but we have to do this together with the IT and communications systems that come with the ship.

As an example, for one fleet manager we work with, where we are monitoring around 50 ships, there are approx. 5,500 machines being monitored every year by our remote diagnostic teams. The crew collect the data on some 12,500 measurement points. Now, that sounds like a lot of effort, a lot of problem, but the fact is what we have been doing for the last eight years now very effectively.

 The first place to start is by understanding what equipment is high, medium, low, and critical. Which machine should I monitor every month? Which machine should I monitor every two or three months? Which machine should I monitor every six months? And by doing this upfront analysis, you get the insight on how to set up program. By segregating the assets in this way, you can get the right region.

What we find as a result of this approach over a period of five six years, is that this fleet operator estimates that high critical machines are around 20%. For those high critical machines, he applies OEM recommendations and CBM. For the medium critical recommendations, which are around 50%, they actually reduce the OEM maintenance and use CBM as the main signal to do planned maintenance. And for the low critical machines, we can virtually throw away the rulebook and move to a basic inspection basis, because this is so low risk.

In simple terms, it is all about the process. Understand the system, understand the components in the system, and understand the maintenance practise that you can apply for planned and predictive performance monitoring. Then, we know the right data to collect and how to make the right judgments on that machine condition.

Each year, around 1400 maintenance recommendations are provided to this fleet manager, of which 40% are invasive and 60% non-invasive, so better maintenance is achieved. We can demonstrate return on investment at least 200% and more on that activity. The CM program is working at a very good level, and is embedded into the organization, and for us also provides sustainable revenue and the opportunity to sell more added value products and services.

There’s a wide range of CM technology in the market, they break into three main groups, portable, fixed and intelligent online systems. There are two main types of CBM services offered as well, either Fleet CBM services, using remote monitoring, or Specialist CM Services, where we send a Marine CM specialist on board the ship, all of which is completely in line with class approved processes.

The Marine industry is a global market, so it is easy for specialist companies to engage locally, but we also need to be local and global. In that sense, we have created a specialist team who are placed around the world in a connected network. To summarize, you should look for those attributes, if you want to go into this area.

Above article is an edited version of Gerald Rofle’s presentation during the 2015 GREEN4SEA Forum

You may view his presentation video by clicking here

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About Gerald Rofle

Manager – Marine Service Development, SKF Industrial Market, Marine

Gerald Rolfe has worked for SKF for 31 years, in a career including roles in technical management, business development, and delivery of Specialist Services. Gerald was Engineering Manager in SKF UK for over 10 years, providing design and engineering advice to SKF customers across all industries, and was then General Manager for SKF Reliability Systems for 12 years, where his team built up a strong reputation with Marine Fleet Operators. Gerald joined the SKF Global Marine Segment in 2010 and is today responsible for SKF Asset Management Services, including the Marine CBM Service Strategy, offering Specialist CM Product and Service solutions to Fleet Owners, Operators and Managers worldwide. SKF is today recognised as the world’s largest supplier of CM technology, supported by a global team of around 1500 engineers and staff worldwide. SKF Asset Management Services include Maintenance Strategy Optimisation & CBM Services, CM technology, Specialist site services and Remote Diagnostic Services, under long term supply & service agreements In 2013, SKF acquired Blohm & Voss Industries, the leader manufacturer of Marine products for Propulsion Shaft-lines, Stabilisers & Steering gear, plus Oily Water Separators and Environmental Monitoring tools”

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