150 ft yacht with 130mm shafts. Problems with shafts.
150 ft yacht with 130mm shafts. Problems with shafts.
(OP)
Hello Everyone,
I am new to this site and could really use some information. I have two shafts 130mm with heavy pitting that I need to have resurfaced and machined. I am probably not using the correct terminology please bear with me. Some of the pitting is 1/2" deep but I have heard that the shafts can have a new surface applied through a welding process and machining. Is there a depth of corrosion that decides when it is time to scrap the shafts? The yacht is in Miami,FL, if someone knows of a reputable machine shop that can handle this type of job please let me know. Or if I am missing important information about the process I am all ears. The spots in question are between two bearings. Please see the attachment for a picture of the corrosion.
I am new to this site and could really use some information. I have two shafts 130mm with heavy pitting that I need to have resurfaced and machined. I am probably not using the correct terminology please bear with me. Some of the pitting is 1/2" deep but I have heard that the shafts can have a new surface applied through a welding process and machining. Is there a depth of corrosion that decides when it is time to scrap the shafts? The yacht is in Miami,FL, if someone knows of a reputable machine shop that can handle this type of job please let me know. Or if I am missing important information about the process I am all ears. The spots in question are between two bearings. Please see the attachment for a picture of the corrosion.





RE: 150 ft yacht with 130mm shafts. Problems with shafts.
Or, you could just ask the nearest yacht yard, or the one you're in; they all have trusted suppliers for most everything, including weld repair of shafts.
Mike Halloran
Pembroke Pines, FL, USA
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
What material are they?
It sounds like you really need to consider an upgrade in the alloy.
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P.E. Metallurgy, Plymouth Tube
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
Mike Halloran
Pembroke Pines, FL, USA
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
Thanks again for sharing your professional experience and advice.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
I don't know any boat people down there, but there are a lot.
I'll ask a friend in Palm Beach who he uses.
There are special alloys used for seawater service. A low alloy stainless grade would last forever in fresh water and even handle occasional runs in seawater. But sitting in seawater take a different class of material.
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P.E. Metallurgy, Plymouth Tube
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
No, I don't do shafts. I worked on yacht exhausts all over SoFla for a few years, so I got to see a bunch of them spinning, none like yours.
You might consider mechanical seals to replace the packing glands.
Mike Halloran
Pembroke Pines, FL, USA
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
Is this yacht operated frequently or does it sit at dock for long periods?
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
You should be looking at alloys with high Cr and Mo.
Such as Aquamet 22, here:
http://www.aquamet.com/home.nxg
This isn't a commercial plug, but I have seen their stuff used successfully in many applications.
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P.E. Metallurgy, Plymouth Tube
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
Another example
thread330-179251: salt corrosion resistance of 17-4 PH
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
A pair of 1,500 hp engines in a 150' boat is quite a package.
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P.E. Metallurgy, Plymouth Tube
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
Mike Halloran
Pembroke Pines, FL, USA
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
No kidding! I just took a look at the website for this boat (or "private estate" as described in the brochure), and it does not look like the owners are hurting for money to pay for repairs.
The cost of machining a new pair of prop shafts from a premium material like Aquamet 25 would probably be less than $40K. Which seems like a relatively modest expense compared to the cost of paying salaries of the Golden Compass's ten crew members.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
Mike McCann, PE, SE (WA)
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
Looks more like an SMAW welder to me.
What makes you think it is GMAW ?
Cheers,
DD
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
Definitely a Miller machine based on the blue paint. The only reason I assumed it was not a stick welder is because there are three cables attached to the machine face.
Also, if you look at the second photo in the post above from captstaats, you can clearly see the remnants of a piece of errant MIG wire just to the upper left of the weld repair.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
RE: 150 ft yacht with 130mm shafts. Problems with shafts.
And what about all of the little pits? Those need to be done away with also.
What material is being used as weld filler?
Looking at the boat specs it says that the engines are 750hp. That makes these very low strength shafts.
Which is good news, since the repairs will not be highly stressed.
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P.E. Metallurgy, Plymouth Tube