Can't believe this genset wasn't over heating...

How about not only failing to fish out the pieces, my boat came to me with 12-yr-old impellers, originals. I'm pretty sure it was the scoop strainers keeping the engines cool during my 500-mile race home, not the shredded impellers. Good thing we were in a hurry. I fished the pieces out of the system, replaced what was left of those impellers.

Yesterday I got to the generator, 100 hours and the bolts had obviously had a wrench on them, figured I was just going to replace it for baseline purposes, but it too was missing two vanes. This was a boat maintained by a professional yacht maintenance service at an expensive marina, not just some owner DIY failure. Hopefully not too many more surprises to come, just a lot of catching up on routine maintenance.

No, this was a boat you were led to believe was maintained by a professional yacht maintenance service. One of two things is the truth. Either the owner didn't contract for these services or contracted and they weren't provided.

Every used boat had perfect maintenance until you ask for the logs and receipts. Then it often falls apart. Often people use yacht maintenance services but only for problems they report to the services and don't get routine or complete maintenance done.

When any of our maintained boats loose an impeller part, I find all pieces and super glue them back together to prove I reclaimed all the parts. Logs are maintained and a true impeller life to expectations are ensured.
350 hours on a 17-20KW, NL is about the norm for an impeller up here with all the river silt.
We strive for gen-set oil changes between 200 to 250 hours. We have learned witch gen-sets get new impellers every oil change or every other oil change. So far in many years, were not to far off.
StJohns river grass & debris contribute to these early demises. It's a feel for the boat and owners operation that helps drive our schedule.
All gen-set raw pumps are replaced (new) every 1000 hours. We don't F**** with rebuilding them, the warranties from the vendor covers the owner better than I can.
However, there are a couple of cores rebuilt as spares as emergency pumps that can be used while deployed. There is nothing worse than a call, the gen-set is down, guest are pissed.

The most demanded on comportment of a ship is the light plant. Spoil it and take care of it well.

Pascal learned it when he had to rotate gen-sets for false oil pressure alarms and shut downs (issue months or longer ago).
Odd both had the same problems but he fixed it, on both sets, improved the system with real pressure gauges and can better manage any oil alarms in the future.

Raw water is a great issue on cooling our gen-sets. Don't cut corners.

Hard to know exactly in this case, maybe the owner didn't want anything but fluids and filters for 12 years. The maintenance company left a large sticker in the engine room with their logo on top, and detailed the fluids and filters changed that spring. And there was a card in the galley with the same info. When I called the company they said they hadn't worked on that boat for years, but their sticker and card were on the boat.

I'm changing the fluids, will send samples to Blackstone and find out where I stand. So far, all the fluids look and smell lightly used.

I replace genset impellors annually, I've found most don't go 2 years without losing a vane or two, regardless of hours...... genset impellors are cheap and quick to replace.....mains I'll go 2 years or 200 hours. Maybe more hours if they're the large cat/man etc ones.....but never more than 2 years.

So what pieces do you need to remove to fish out vanes?

The Mississippi is pretty bad too and you'll even eat up the raw water pumps in a few years there.

Yep, this is what I've been saying about the silt eating impellers around here (Ortega FL).
Folk talk about impellers lasting two years or near a thousand hours. One year or 250 hours around here.