Marine Machinery Overhaul and Repair time

[Marine]

Hi,

I am looking for ship machinery overhaul intervals, repair times (man-hour?) and possible failure rates. Important machinery include; Main engines, diesel generators, shaftings, steering gear and rudders etc and if possible to component details. Can some marine engineers help or give a pointer where could such details or data be found please?

Thanks in advance
:)
Anzac

[ArkSeaJumper]

Can you give us a little more backround information, it would be very dificult to say, or it would be very general information.

regards

[Marine]

Thanks for the reply ArkSeaJumper, Backgorund is that i am inteterested in calculating machinery availability, thus need two parameters atleast i.e. mean time between failures and mean time to repair. such can be judged from machinery failures, overhaul intervals and the time it takes to repair. For eample, say a built on fuel system includes; fuel injector, fuel pump, and fuel piping. If i wish to calculate fuel systems availability, i would need to know failure intervals and the repair time of each items mentioned. In other words, If the detailed component data is known then parent machines overall availability can be calculated in this systematic fashion. Ofcourse ideally all systems should be taken into account, however, it could be possible to make an approximation with whatevrer is available.
In short, maintenance and failure or overhaul intervals data to whatever component level detail is needed on important propulsion machinery i.e. Main Engine, Gear Box, Shafting, Propeller, Diesel Generator and respective Electric Drives if it is an electric driven ship.

I am making a detailed table where important propulsion machinery items are listed to component level details. If needed i can send that too if you are interested.

Again, thanks for the reply. regards

[ArkSeaJumper]

Sorry I wasn’t clear enough, what I was trying to say is you will have to pick specific components on specific engines.

To show you what I mean, I did a quick check on the injector maintaince hours on three types of engine.

Wartsila 38B Injectors: 2000 Hours
MAK M25: 4000 hours
MAK M20: 6000 hours

These hours are derived from both the engine makers and our own experience (the engine makers often refer to the end users for practical operating hours).

I cant see how you can design a general hours list.

Regards

[Marine]

Thank you for the reply. You are quite right in pointing out that specific manufacturers may have different overhaul intervals and hence failures. I was thinking probably the difference is not too much and one could 'average' numbers. In any case, It would be great if you could help me with some detailed data on engines (on engine manufacturer basis too, if possible) and items as menioned before. Ofcourse this may take considerable amount of your time and I fear I might be asking too much for free :). Ofcourse engine power is important too.

Another quick one, would the same engine overhaul intervals vary quite much on duty basis? for example Engine XYZ is employed on propulsion duty and on another application same Engine XYZ is employed for power generation, would the overhaul and maintenance periods be different then? ofcourse while thinking of load and transient conditions the propulsion duty engine seems to suffer more. Any comments?

thanks again, & Reg,

[TxMarEng]

GenSets are frequently seen to have extended service intervals due to their steady state loading. Large two strokes are generally seen to have longer service intervals in propulsion duty than equivalent four strokes. In the end it's all up to supplying clean fuels and lubes of the proper quality. Separators although perhaps the most important element in a large plant unfortunately seem to be the most mis-understood and often neglected piece of equipment in the engine room. Westfalia has just opened a new training center in Hamburg so that will go along way towards educating the masses. That is if the companies will pay for the attendance.

[Dieseldame]

I'm inclined to ask the purpose of the document you are preparing. It sounds like a good project but agree with the comments of other posters about equipment specific information. I guess I would add my two cents in that maintenance schedules play a big role here. You are quite right to point out that gensets have different duty configurations than main engines, I have seen reports from the manufacturers showing what options are available depending on the intended us of the engine. Simple example. If a main engine is unlikely to be run hard it may be better to not have one equipped with a turbo charger that requires a specified RPM to operate (lets say 1800 rpm). So, if the engine generally runs at 15 - 1700 rpm..its it likely to carbon up since it was designed to run with a turbocharger - more repairs, shorter run time. In short, might be worthwhile to contact the manufacturers to see what resources they have available on the analysis side.

DD

[Marine]

Thanks for the reply. The purpose of this document is academic work and personal interest as well. I sailed for sometime and feel that assumptions or whatever the engine maker writes in manuals are far away from reality if not all then in some cases atleast. So I asked current engineers for help. I am requesting repair times and overhaul or failure intervals based on experiences, precisely if possible. Anyone up for help? ( I have the list on few pages with specific items)

thanks again!

[JK]

IMO, when Cat says do something to an engine at this many hours, you better do it. The only time I have seen failures at an earlier time is the Cat models that the engines are boosted in power. The operating instructions have to be followed to the letter or they will drop head valves.

We use predictive maintenance and LO analysis to extend machinery surveys out. Not anecdotal evidence.

[ArkSeaJumper]

Normal rules do not apply with CAT, and I have been caught out on this.

One Christmas the Chief on a coaster rang me up to say the crankcase pressure alarm had gone off, high but not through the roof.
I assumed I had a few days to organize everything to do the offending unit. Not with Cat.

I don’t like CAT marine engines.

[JK]

LOL
Does anyone?
The only good thing is there are dealers everywhere.

[Wyatt]

Cat does not make marine engines, they create engines that can be placed in a container and run, be it in a ship or a drill site. I don't enjoy cat engines, auxillary pumps to tight together and very sharp castings in the crankcase. But one thing about cats is that they can be abused. I have seen a 399 after it was run with a dropped valve. the engine was run for a week! I was told on a report to check the valve lash, a little noisy! Well hell yea, one valve was gone and had basically pushed its way through the piston. Unreal. That was 24 years ago and that engine is still pumping out power today.

[JK]

You still running a 399? Having problems getting the fuel pump casings?

[Wyatt]

We still have 3 vessels with the old 399's. The configuration is 4 main engines each connected to a Cat 7261 gearbox, which we call the little yellow bastards. The company has been slowly modernizing, we have had 2 vessels changes over to the new Cat 3512 series coupled to a new Lufkin gearbox. Parts are becoming an issue but as yet we are still able to get the parts we need, touch wood. The vessel I work on has a couple of EMD 645 12's. These are even older!

[JK]

Last time we needed a casing, we managed to get 1. Next effort would have been EBay or Alang!
We only had two of the beasties, someone else has to worry about that particular little problem now ship's under someone elses management.