Condition Based Maintenance (CBM)

According to Wiki, CBM “is maintenance when need arises”. In other words maintenance is not performed until at least one indicator shows that you need it.

CMB saves time and money. When done properly your equipment last longer because you have the pulse of the machinery at all times. It uses real-time data to prioritize maintenance tasks.

Example 1: let’s say you have twin inboards. And for example it might cost you $200 to have the oil changed. The manual says change the oil every 100 hrs. After 100 hours you have the oil sampled and you find out that it is ok. You do that every 50 hrs (alternating between port and starboard engines) after that and end up getting 400 hours out of an oil change. If you went based on the manual you would have spent $800 on 4 oil changes but with CBM you changed the oil once. The oil analysis costs $25 per sample or $200 for 8 samples. You saved $400 or 50%. Not to mention the environment time in the shop etc. In practice you will probably find you can get much more out of your oil than you think, especially with synthetic oil.


Flexible impeller after 10 years.

Flexible impeller after 10 years.

How about other maintenance items; how long does your raw water impeller last? see the above picture. Mechanics will say change it every year. Yamaha F225 service manual says 500 hrs or 3 year which ever comes first. Word at the dock is: they will always last 2 years, maybe 5 years, better to be safe than sorry. Since it costs $300 to have it changed, why not change it when it needs it?

Example 2: you have twin I/O or Twin outboards. It’ll cost $600 every time you change the impellers. Instead of changing it every year you install a flow rate meter and/or exhaust manifold surface temperature monitor. You find out that after 5 years the surface temperature of the exhaust manifold increases over 140oF and the flow rate decreases. So you change it after 5 years instead of every year. You just saved $600 X 4 = $2,400.

I’d like to hear what you have to say about this. Give me a comment. Can you think of other things that could be CBM? Do you think it would be worth it to install CBM monitors? What other monitors do you think would be good?

leave a comment. Or send me an email.

I’m waiting to hear from you


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