For clarity. Are the shafts ferrous and therefore capable of magnetic particle inspection, magnafluxed. I would have thought dye penetrant testing would be a suitable test for the likely defects.
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Re: Cutlass bearing or something else?
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05-23-2020 06:42 PM #12
Re: Cutlass bearing or something else?
Shafts are ferrous, so mag particle OK. Dye penetrant vs mag particle is kind of a “best anchor” subject. Mag particle is less fussy about part cleaning and surface irregularities. It will find near sub-surface defects, although I don’t think that would be meaningful in this case. It’s typically a faster test than dye penetrant. I’ve never procured a one piece mag particle inspection, so not sure about the cost - if it was a couple of hundred bucks, I’d be pretty happy. Big yards that do a lot of shaft and wheel work probably have sources; if not, I’d look for an automotive machine shop that does crankshafts, probably the lowest cost.
Last edited by wpc691; 05-23-2020 at 06:56 PM.
Mike Peters, 1985 43MY, Cat 3208T, Blue Bayou; 2011 Key West 246BR, F250, Baby Blue; Punta Gorda FL
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Re: Cutlass bearing or something else?
We had a similar boat. An 85 with detroits. We did the bearings but not because of noise. We were doing the seals and tuning the props and went for them since the rubber was peeling from the bronze.
I don't think our boats were high strung enough to warrant all of the extra exams. Larger yachts that run on plane with large diameter shafts sure.
But I wonder about the value added by extra exams at this size. I think a good visual will probably suffice. We had 1 3/4s in Freedom.Regards
Dan
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05-23-2020 08:18 PM #14
Re: Cutlass bearing or something else?
Mike Peters, 1985 43MY, Cat 3208T, Blue Bayou; 2011 Key West 246BR, F250, Baby Blue; Punta Gorda FL
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Re: Cutlass bearing or something else?
On my only experience with cracked shafts, nothing was visible with the naked eye until they were magnafluxed or whatever die was used. That was a 3 1/2 “ AQ22HS on a planning boat used probably 50% of the time planning
Pascal
Miami, FL
1970 53 MY #325 Cummins 6CTAs
2014 26' gaff rigged sloop
2007 Sandbarhopper 13
12' Westphal Cat boat
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05-24-2020 12:09 AM #16Senior Member
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Re: Cutlass bearing or something else?
Dye-pen is cheap and you can do it yourself.
FTFD... i drive a slow 1968 41c381
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Re: Cutlass bearing or something else?
Dye-pen is cheap and you can do it yourself.
Where I was going Krush. Spent most of my life inspecting stuff and most on this forum I imagine can buy an aerosol can each of dye and developer and do their own shafts.
Clean the area, spray on dye, wipe off and spray on developer. Look for pink lines, cracks. If any get professional advice.
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05-24-2020 03:04 PM #18Senior Member
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Re: Cutlass bearing or something else?
if the shaft is occilating it's usually an engine alignment issue. Did the squeal go away when you idled it up while in gear? Can you tie the boat off at the dock and put the boat in gear and try to locate the noise?
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05-24-2020 03:44 PM #19
Re: Cutlass bearing or something else?
Yes, putting it in gear at the dock is my next step. If that shows nothing, I’ll repack the stuffing box and assess shaft rotation. I did note that the keyway on the shaft is 1/2” out of the coupling and the key right at the end of the slot. On the other shaft, the keyway is inside the coupling, and the key 3/4” inside the coupling. But, there is paint overspray on the shaft that makes it appear it has always been this way, as odd as it seems.
Mike Peters, 1985 43MY, Cat 3208T, Blue Bayou; 2011 Key West 246BR, F250, Baby Blue; Punta Gorda FL
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05-25-2020 12:41 PM #20Senior Member
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Re: Cutlass bearing or something else?
Sometimes the keys will be loose enough to slide up and down the coupling’s keyway. The main thing that you want to check is where the shaft is running in the shaft log. The engine will usually settle on the reduction gear end causing the shaft to rub on the bottom of the shaft log. Not sure if your diver was able to check that with the boat in the water. If you have the coupling in-bolted you can pull up on the shaft to try to tell were the shaft is running in the log. Much easier to check when the boat is hauled out but, I don’t know what the capabilities are where the boat is located. Once you get above an 1 1/2 shaft it’s pretty hard to get the shaft to move much with the weight of the shaft and the thickness of the hose on the shaft log.