Monthly Archives: February 2012

The argument for equivalence between scheduled and condition based maintenance manuals has been set.

Prescriptive or Rule Based!

In these modern times the maintenance manual that accompanies each new piece of machinery that is installed on a ship or platform can no longer be used to limit the guarantees offered by the manufacturer to setting prescriptive periods at which certain activities must be performed to achieve support of the OEM in the event of an unforeseen failure.

By their very nature these documents play to the lowest common denominator as the duty, location, environment , expected function, skill of operation and maintenance, etc., cannot be known for every installation therefore the recommendations must account for this and may as a result be sub-optimal.

Equipment makers need to recognise the option to maintain by condition and in doing so value that the operators who aspire to become world class performers will outdo their expectations and drive the envelope to maximise the value of the asset by maximising efficiency.

Maintenance manuals for all machinery would be wise to include a detailed FMEA as a minimum, possibly seperate FMEA’s for general expected installations. Clearly these will only be part of the story as the owner of the asset will have to complete the FMEA in respect of local conditions, maintenance expectations and environment, but at least the asset will start its life under the joint co-operative umbrella of a best practice approach.

It is my sincere belief that purchasors and specifiers should endeavour to ensure that only companies who provide this data are included in their respective tender process.

No need to open main bearings on Man Diesel Engines

Click to view SL2012-522 Main Bearing Inspection

Man Diesel now state clearly that bearing removal is not recommended as normal practice and therefore not recommended unless evidence based reason dictates.

This is a clear indication that best practice has shifted from a direct inspection methodology to a condition based approach.

This represents a shift in emphasis where the OEM clearly states that opening bearings without cause is likely to increase the risk of issue, either directly by the introduction of new sources of failure such as dirt or re-build issues, or by implication by reducing the support in terms of warrantee, where non recommended strip down may in the future invalidate terms.

Herein a video of the process for bearing removal courtesy of Marine Insight (Apologies for corrupted quality at the end! DS)

Article in LNG World – Maintenance


This is a short article that was created for LNG World and describes an overview of the soon to be available Machinery Condition Based Maintenance descriptive note which can be applied for companies who wish to operate their maintenance management on a risk based approach.

In essence this means that all nominated machines are maintained purely on the basis of condition as dictated by the condition monitoring analysis performed. In reality this means that NO item need be removed from service and required to be opened out for the purpose of credit for survey unless the CM data and associated records are unsupportive. Due dates will be removed and in all cases where condition continues to be acceptable items will not need to be withdrawn for inspection.

This is a high standard to achieve as it requires the cultural capability to manage risk based maintenance systems. It shall be viewed as an aspirational standard which rewards those who seek to exceed the minimal compliance requirements of the regulations but is also robust as the condition status has to be demonstrated as known on a continual basis.

We expect that there will be a number of companies who can move into this regime quite quickly but that what will happen is the vacuum that is created by this will be filled by companies who wish to perform at a higher level but who have some minor issues such as resourcing or implementation concerns. We will also be providing resource to assist these organisation to optimise their operations and move forward to a ensure that all operational and reliability related risks are As Low As Reasonably Practical – ALARP – a concept that must ultimately become accepted in the marine industry.

Can Classification Societies really align with Condition Monitoring?

Classification and Condition Monitoring

One of the things that seems unusual is that whilst approximately 10% of classed vessels have their planned maintenance systems recognised by their classification society. This allows the Chief Engineer to credit a number of items for survey at some convenient time, only about 10% of these use approved condition monitoring process which the Chief can use to avoid opening these assets purely for the purposes of satisfying the regulatory requirement.

What that means is that only 1% of ships use condition monitoring for the purposes of classification. It is suspected that a significant number of vessels successfully employ some form of condition monitoring on a regular basis and may even use condition as a foundation for their maintenance strategy but do not take up the opportunity to align these processes with their classification society and therefore must be performing unnecessary invasive surveys and in doing so increasing the risk to reliability.

Why is this?

Marine Machinery Condition Based Maintenance

The world of the marine engineer is changing and instead of maintaining machines best practice is to maintain reliability. What I mean by this is that the act of maintenance has traditionally been one based upon the performance of tasks at predetermined intervals. These would vary in scale from simple checks and cleaning to performing a full strip down for overhaul and component renewal. Therefore the required skill was to be able to understand how to perform these tasks and return the machine successfully  into service.As a result of improvements in design and a tendency to reduce the need for running repairs, there has been an increase in the use of throwaway components, e.g. sealed for life bearings. Coupled with the ever present need to operate at reduced  cost means that more often nowadays the engineer is tasked with developing strategies to understand and react to condition thus avoiding or extending scheduled intervals of intervention until necessary. This approach is broadly described as a risk based approach. The engineer is now not maintaining the machine but maintaining the reliability of the machine.

The question to be answered is whether the emerging technologies and practices  can be adequately implemented using staff who’s training is based upon traditional engineering principles when what is required is different. Not that engineers are not competent or sufficiently skilled to adapt, but whether the companies who employ them have developed and matured sufficiently to allow them to work in a different way.

Maintenance handbooks produced by manufacturers must by definition stipulate activities for every end user to reach an acceptable degree of reliability. This means that in the main most machines MUST be either over maintained or being maintained in a way that relieves  the manufacturer of any liability in the event of a failure within the period of guarantee. Even when machines are in service beyond the traditional period for which guarantees are in place, in the event of a failure sufficiently significant to invoke the need for a claims or loss adjustment exercise, the company in question will find itself at higher risk of penalty due to reduced cover.

This the employed skills, the company culture and the risk protection devices are misaligned when compared to industry best practice. It is easier to employ traditional and hence sub-optimal methods to maintain machines in the marine industry.