Prop Shaft unattached itself from Trans.

[apagano]

Help please , advise needed quickly, i am presently cruising down ICW and am in South Carolina 30 miles north of Georgetown and my starboard prop shaft disengaged from transmission. Local mechanic informs me I need a new shaft and all hardware that goes with it. meanwhile He is trying to make a temp connection so I can steer and put my trawler in a better berth. The shaft end is worn down a couple of thousands of an inch and is slightly pitted. I am in need of advise regarding a full replacement, would I have any other options? Feedback would be appreciated. BTW my boat is a 40 Marine Trader with 2 lehman 120 engines. Thank You
Alfonse

 

[obthomas]

Pictures?

 

[High Wire]

Are you saying the shaft pulled out of the coupler and will no long stay put?

Does it have setscrews? Maybe sheared off?

 

[steelydon]

Did it shear the bolts at the coupler? I had a bolt come loose and the other 3 were loose. Caught it on an engine room inspection but it would have sheared soon. Or did the coupler come loose on the shaft? If so it seems that a repair could be made without replacing the shaft.

 

[psneeld]

There are quick fixes with limitations...ones that would draw fire from self appointed safety experts.


MY advice is call a machine shop or two and see if they have suggestions. Try one near a large boating area say near Charleston too. Would be good if they did a lot of commercial vessel work.

 

[apagano]

Yes, the set screws ( bolts ) were both sheared off. The set key is still there.

 

[apagano]

The coupler is fine

 

[jleonard]

Without knowing the exact extent of the "damage" it's hard to suggest anything other than a new shaft, coupling, hardware, maybe cutlass bearing. Probably will have to haul the boat to fix.

Just saw your reply, disregard some of what I posted.

 

[Ski in NC]

If it is a solid coupling, you may be able to replace it with a split coupling that can clamp onto a slightly worn shaft. Split couplings are readily available at marine hardware houses.

Should be able to install it without pulling shaft.

Split couplings are better all around than solid couplings, get two and at next scheduled haul replace your other side.

 

[boatpoker]

The shaft end is worn down a couple of thousands of an inch and is slightly pitted.

Reluctant to offer advice without seeing the shaft however, "slightly pitted" would be a concern.

The photos below show an x-ray of a single "pit" and what was left of the shaft under the surface.

 

[High Wire]

There is also a way to add spray welding metal to a shaft if the rest of the shaft is ok. Machine shops can do it. Here is the video that shows it.

 

[psneeld]

Had mine done in Wildwood, NJ after they inspected for more than surface roughness...think the shop is closed now.


It has worked for 8 tears now..but there is always more rust in that area than the rst of the shaft when it sits for months.

 

[steelydon]

I'm with Ski. This fix may be permanent or at least will get you to a place and time of your choosing for an assessment. I have a split coupler on mine which is not dependent on set screws.

Good luck

 

[DavidM]

I was helping a friend bring his boat up the ICW when the coupler bolts sheared, the prop shaft pulled back and partially jammed the rudder. But new bolts and a come along to pull the prop shaft up got us underway in a few hours.

It may not be as bad as you think.

But it is impossible to know without detailed pics. I would go with the quick fix which sounds similar to what we did to get you going and then reassess when you have the time and place to do it.

David

 

[Comodave]

I am putting split couplers on my boat, did 1 last winter and am doing the other one next week. They may be able to accommodate a couple thousands of an inch. Or it the shaft worn at the shaft log?

 

[wkearney99]

I was helping a friend bring his boat up the ICW when the coupler bolts sheared, the prop shaft pulled back and partially jammed the rudder. But new bolts and a come along to pull the prop shaft up got us underway in a few hours.

A previous boat of ours had crap fasteners on the v-drive coupling. They'd either work loose or one finally snapped. I replaced all of them, on both engines, with proper strength bolts, washers and nuts and never had trouble again. I was fortunate the spinning shaft never slid back far enough to whack a rudder, nor mar the through-hull coupling.

Was there any driveline vibration before this? Because if there was you might be due for an overall realignment of the strut and other parts. That same previous boat grenaded it's starboard v-drive (lost oil pressure due to crack fitting) and we had it totally re-aligned. It was a night-and-day difference in ride quality after having that done.

The upside to heading south is you should probably have better choices for repairs on the shaft and various other parts.

 

[apagano]

https://www.trawlerforum.com/forums/attachment.php?attachmentid=110410&stc=1&d=1606152022

 

[apagano]

jpeg.gif A04A2095-0443-447D-B593-96A83303D2D6.jpeg (106.7 KB)
jpeg.gif 89C08124-892F-4A2D-A5F8-F6EC95A7BAEC.jpeg (127.1 KB)

 

[SoWhat]

Insufficient information. Photos would help. (Your links aren't working)
If the shaft is intact, then as many others have mentioned, a split coupler will get you down the highway.

Most prop shops won't spray weld a shaft under 2" in dia.

 

[Lepke]

1) You can take the shaft to a machine shop and have it built up with welding or metal spray and then turned to size.
2) You can turn the shaft end to a slightly smaller size and boar a new coupling to fit (not the best long term way, if not machined right will eventually break).
3) Depending on how much shaft is between the trans and shaft seal, you cut a foot or so off the shaft and install an intermediate shaft. My current boat is set up this way. You have a coupling at the trans and another where the two shaft pieces meet. Mine has been working this way for about 50 years.
4) Buy a new shaft.


Metal spraying the shaft works well. The shaft needs to be turned slightly to a uniform surface. A good operator can add as little as .001" at a time. I used it for zinc coating mild steel and repairing printing cylinders.

 

[Solly]

If it's only the setscrews that have snapped and the key is good you can just replace the setscrews for a temporary fix to move. Low speed and RPM.
The shaft being undersize is another worry. It may not center in the coupling and vibrate or not run true when spinning.
Maybe have a machine shop true the coupling end and fit another coupling.

 

[FF]

To get underway simply drilling the shaft and installing a tapered pin will last till you get a split coupling .

 

[oguidry]

Call Safe Harbor City Boatyard in Charleston at (843) 884-3000. You can text them pictures. The yard has a mobile service if you need help with a temporary fix.

 

[bayview]

If there is still a key why not shim the shaft and tighten the screw?

 

[kapnd]

Was there any driveline vibration before this? Because if there was you might be due for an overall realignment of the strut and other parts. That same previous boat grenaded it's starboard v-drive (lost oil pressure due to crack fitting) and we had it totally re-aligned. It was a night-and-day difference in ride quality after having that done..

It’s important that the cause of the damage is discovered and corrected, or the problem won’t go away!

 

[Andiamo2018]

I have worked on this problem a few times. The last two had clear causes and things that needed to be fixed.

Usually it is caused by the engine being out of alignment (starting at one end or the other) which causes the vibrations and eventually failure.

In one case a line got wrapped around the shaft and jammed between the prop and strut. It stalled one of the twin engines and that was enough. It took two more months but the coupler bolts broke. When that happened the shaft got bent as well as a couple of engine mounts.

Insurance will cover ALL of it if the problem was NOT maintenance.

Each time engine mounts were replaced, new stuff installed and aligned.

Usually something makes those bolts - key ways etc to break. i've actually never seen one break on a well aligned engine that had not had at least a 'soft strike' or something that wacked it all out.

 

[McDan]

Help please , advise needed quickly, i am presently cruising down ICW and am in South Carolina 30 miles north of Georgetown and my starboard prop shaft disengaged from transmission. Local mechanic informs me I need a new shaft and all hardware that goes with it. meanwhile He is trying to make a temp connection so I can steer and put my trawler in a better berth. The shaft end is worn down a couple of thousands of an inch and is slightly pitted. I am in need of advise regarding a full replacement, would I have any other options? Feedback would be appreciated. BTW my boat is a 40 Marine Trader with 2 lehman 120 engines. Thank You
Alfonse

It might be possible to have a new flange machined to match the new, smaller tapered O.D. of the shaft after IT is cleaned-up, and after it’s found to be ‘straight & true’- but if it’s not ‘true’ you then might try having it straightened first- but if that fails you’ll pay for the effort and basically throw that money away with the warped shaft. Chances are a replacement, as your mechanic recommends, will be best.
Keep in mind you’ll need a new flange as well as having the two faired at a machine shop.

 

[ben2go]

If he has a shaft that isn't running true, no amount of work will keep it together for long until the shaft is pulled and straightened or replaced. On some boats, it doesn't take a lot of run out for the shaft to shake lose the coupling. By this point the boat should feel like a paint shaker though while running.

 

[Bryant]

shaft

Help please , advise needed quickly, i am presently cruising down ICW and am in South Carolina 30 miles north of Georgetown and my starboard prop shaft disengaged from transmission. Local mechanic informs me I need a new shaft and all hardware that goes with it. meanwhile He is trying to make a temp connection so I can steer and put my trawler in a better berth. The shaft end is worn down a couple of thousands of an inch and is slightly pitted. I am in need of advise regarding a full replacement, would I have any other options? Feedback would be appreciated. BTW my boat is a 40 Marine Trader with 2 lehman 120 engines. Thank You
Alfonse

I don't know anything about what's available in your area but you might try calling Huckins Yachts in Jax, Fl to see if they have a mobile crew that can come to you, diagnose what's wrong, and fix it. Tow Boats US Gold program will tow you from where you are to a yard that can work on your boat, if you happen to have that coverage. If not, get it for next time. For now, call Brian at American Diesel at 804-435-3107. If that doesn't help, call Mark Hyma in Pensacola, Fl. Best Diesel Mech on the Gulf Coast. Does all the work on my FL 120 and has been amazing. He might be able to help you. 850-760-2466.