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So I recently got a spot on a crab boat here off the southern Oregon coast and they found out I had experience (although limited) in diesel mechanics. Well, they made me the boat mechanic and I’ve never worked on or learned anything about marine diesel engines. Just noticed a few differences and specifics I have some questions about. The boat I’ll be on has a new Cummins QSB 5.9 355 hp engine so I would especially like to know it was installed right. I’ve attached pictures of the way the exhaust is set up because I noticed the injection point for water is on the same side of the riser as the turbo. To me it looks like water would drain right back unless there is some baffles or something in there. Also the fuel system has two large fuel filter/ water separators with a three way ball vale so you can isolate and service one. That’s the whole filter system though. Shouldn’t there be another spin on filter in line with a smaller micron rating? I also don’t see a hand pump to prime fuel. Like I said I don’t know much but if there are any other things I should look for or known common issues please share.
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Vessel Name: Tenacious
Engines: 6BTA 5.9 330's - "Seaboard Style"
Location: Long Island, NY
Country: USA
Doomed to Fail Link
Here is plenty of reading on exactly what you are dealing with..
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Vessel Name: Tenacious
Engines: 6BTA 5.9 330's - "Seaboard Style"
Location: Long Island, NY
Country: USA
Doomed to Fail Exhaust Setup
Your take that something is not right with the exhaust is correct. However, the water is not injected into the exhaust gas at the point where the raw water hose connects to the elbow. That elbow is what is known as a jacketed wet elbow. The water comes out the far end in a spray ring (aka showerhead) pattern. Attached is a very exciting video clip I made before scrapping that very same elbow. You can see the spray ring.
What is good about that exhaust you show is that there is some height in the system and what looks to be very good height in the engine room, not all of which is being used. What is not good is that the jacketed chamber of that elbow holds water when the engine is shutdown and sitting at the dock. Those elbows were designed to be installed pointing down so they drain on shutdown. But they are often used to make the poor man’s riser as in your case. It’s on borrowed time until it fails internally and floods the turbo, exhaust manifold, etc etc.
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