Suggestions needed for removal

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CharlieO.

Guru
Joined
Sep 21, 2020
Messages
1,574
Location
Lake Champlain Vermont, USA
Vessel Name
Luna C.
Vessel Make
1977 Marine Trader 34DC
Looking for suggestions on getting the shaft log/tube removed. This is as far as I can get it being hitting with hammer from the inside. Putting a pipe wrench on from the outside just started to crush the tube with out turning it at all.
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The rest of the pipe is buried in concrete ballast. Now the only access I have is from the outside. The inside I could possibly get some kind of drift to hammer on but swing access is pretty limited. I would describe the swing access as a little harder than just tapping.
Inside of pipe is fairly smooth looking definitely has some wear/holes on the other end.
 
Do you care if you damage the tube? IOW, will you replace it?

If you are replacing it.... lube the crap out of the top, put a wooden plug in the bottom to prevent crushing (or several short pieces of inserted pipe of smaller and smaller diameters) put that wrench back on and twist/pull away.

If that doesn't work, find a steel pipe cap that will screw on the end, drill a hole in the center then beg, borrow, buy or steal the biggest slide hammer you can...they can do amazing things.
 
I am not reusing the tube, the threaded end on the inboard side was worn all the way through the pipe so not really reusable. The tube was pretty much flush once I started. What you see now is how far I was able to tap it out from the inside. Getting something to thread on the outside of the tube will be difficult since I already put the pipe wrench to it. I have been contemplating how I could use a slide hammer on it since I was already able to tap it that far. I’ve thought about drilling a hole through the end to put a bolt through and figure out how to attach a slide hammer.
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this shows the amount of wear in the inboard side and you can see one of the holes in the bottom. This is what the tube was threaded into in the inboard side then the packing was attached via a hose.
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I would try putting a steel cap on the aft end. Then drill through the cap and pipe. Put a large bolt through the pipe and cap. Then put some smaller pipe inside the current pipe from the forward end. May have to put threaded pieces together to make it long enough to reach the aft end of the current pipe. Then hammer it from the forward end and see if the new inside pipe will drive the old current pipe out.
 
find a steel pipe cap that will screw on the end, drill a hole in the center then beg, borrow, buy or steal the biggest slide hammer you can...they can do amazing things.
I am solidly with Paul. Make yourself a slide hammer. Biggest problem is cleaning up your partly damaged threads - use a Dremel disc maybe. You only need about 3 threads of engagement to develop the full strength in tension of the tube - it will be a better connection than a cross-drilled hole.

Note - you must PULL the tube if you can, not push it from inside. Pushing from inside risks making the tube "swell" with obvious negative impact.

Other tricks you might consider: I would look for easy ways to make the tube looser.

Option 1 - put dry ice in the tube to shrink it.

Option 2 - use a welding machine to pass a high current (100 - 200 amps??) through the tube from one end to the other. Let the tube get red hot. The tube will relax a bit and after it cools down it will be a looser fit.

If things get really ugly you may have to consider cutting a longtitudinal slit in the tube. Probably by a manual "broaching" setup.

Good luck!
 
Wondering if you could make a dowel that would easily fit inside the pipe, and use it as a pilot for a hole saw to cut away some of the pipe. Then take a piece of 1/2" square stock 8' long, and fashion a chisel at one end to collapse the pipe in on itself.

As a last resort, I'm wondering if you could get a band saw blade for cutting metal and cut it open. I've cut out cutlass bearings with a Sawzall. The idea would be to have a 7' blade with handles on each end. Start cutting the exposed pipe on an angle until through and then gradually change the angle to slot the pipe. It might take more than one cut.

Ted
 
As for attaching to the tube for a slide hammer, there are some options which engage on the inside diameter. A device like an expanding wedge concrete anchor? Also, the oil industry uses expanding grippers to hold a test plug to pressure test pipelines at up to 15000psi. (Hydrostatic Pipe Test Plugs). Something that could be imitated.
 
Provided whatever fitting was threaded onto the exterior end of the tube can still be effectively threaded back onto the tube, this fitting has a wall thickness of about a 1/4" and the tube itself has a smooth exterior wall, plus you have access to a couple of pieces of 1/4"+/- alum. plate, say 6"x 6", 3 - 4' long pieces of 1/2"-13 all thread, a handful of nuts & washers and can drill the right sized holes, you can pull the tube out quite easily, if indeed you tapped it out with a hammer the 1"+/- shown in your picture.

No slide hammer, boat incinerating red hot tube, broaching (near impossible) or dry ice should be required.

The real question is, once you have it out, do you have its replacement sourced?
 
Are you actually solving the problem with the shaft log with replacement? Looks like the prop shaft wore out the bottom of of the log. Probably due to collapsed motor mounts. If the motor mounts are replaced or adjusted you can probably center the shaft and epoxy the bottom of the log back to size and be fine as far as leaks.
You can straighten out the other end again with a muffler expander, just don't expand it to far to hold the cutlass bearing.
 
I'd hate to epoxy only the hole/wear spots I can see only to have continue to leak due to the unseen. For others that I have followed this is not an uncommon problem with these boats. I have even talked to a couple boat owners of the same make/model as mine that this problem lead to near sinking of their vessels. Just due to the original construction and parts used in building it seems complete replacement is the best safe option. I know I will never recover the time and/or money this will require but the peace of mind while using the boat with my family aboard and not worrying about the next owners when we sell her is invaluable.

I am assuming since others have had this project done I should be able to find the parts/supplies needed to put it back together. I know there is a place out of Maine that does shaft logs out of fiberglass.

Thanks to everyone that has offered their ideas and input so far. I am leaning toward the slide hammer idea so far, just not sure I can rethread a cap onto the end of the shaft so still contemplating how to attach the slide hammer to the shaft yet. I am still thinking of putting a bolt and nut all the way through the end of the shaft as I see some slide hammers have a j hook attachment that I could use to grab that bolt.

Still open to other ideas....
 
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I'd hate to epoxy only the hole/wear spots I can see only to have continue to leak due to the unseen. For others that I have followed this is not an uncommon problem with these boats. I have even talked to a couple boat owners of the same make/model as mine that this problem lead to near sinking of their vessels. Just due to the original construction and parts used in building it seems complete replacement is the best safe option. I know I will never recover the time and/or money this will require but the peace of mind while using the boat with my family aboard and not worrying about the next owners when we sell her is invaluable.

Still open to other ideas....
Keep in mind that the propeller shaft log is not considered a wear item and was designed to last the life of the boat. That shaft is suppose to run in the center of the log and not touch and wear the sides. That wear is caused by a problem and the most likely problem is unstable motor mounts allowing the motor to shift around. Aligning the motor once the log is fixed will not solve the problem.
Unstable motors are most likely caused by deteriorating motor mounts or motor bed coring rot where the coring will no longer hold the mounting bolts. Most Taiwan trawlers have wood cored fiberglass motor beds. The problem is not likely to be visible on just an inspection or getting ahold of the engine and trying to move it around to see if its loose.
One way or another, a problem exists to cause the issue you have. Fixing just the log will not solve the issue and JB weld both sides of those holes should not wear if that problem does not exist. Epoxy done right will not leak or most of our boats would be on the bottom.
My advice of course, is worth what you paid for it.
 
I like the idea of drilling through so you can then insert a bolt or rod. But rather than use a slide hammer, instead try a combination of rotation and pulling. Attach a large ratchet strap to the bolt where it passes through the tube, and anchor the other end to something big and heavy, like a vehicle. Apply pulling tension with the ratchet strap, and then use the rod/bolt end to twist the tube back and forth. Hopefully the combination will allow you to slowly pull it out.
 
Pierre, I do agree with everything you're saying I do plan on realigning the engine and most likely replacing engine mounts as part of this project. I also need to repair/replace the crossmember that the shaft log was bolted to. Pictures of other peoples removed shafts logs that I have seen the holes seemed to be due to corrosion of the stainless steel. I have spent countless hours contemplating and researching this repair job.

There seems to be two schools of thought from people that have done this or had it done.
1. It wasn't that bad.
or
2. I'd never do that again.

I have yet to choose which one.

I am definitely learning a lot about what to look for in our next boat and what pre-purchase questions to ask.

We bought this boat to learn on, both boat handling and boat ownership/repair. We've gotten our monies worth on the education we've received:).
 
I might be tempted to grind out a large slot in the side of the keel. Remove the shaft log, then do the fiberglass repair afterward.
If that would work depending on construction.
I would think that would be easier than dicking around with other methods.
Im not afraid to do fiberglass work below the waterline.
 
I've seen that done via YouTube, that looked daunting. I'll get back up there this weekend and start pulling again, I've also wondering if I can't get it removed about the possibility of running a new tube inside the old one.
 
This problem is not uncommon on Taiwanese trawlers of this vintage. My belief is that it is a corrosion problem in most cases. My previous boat suffered this same problem.

Fibreglass tube is the best replacement option (IMHO).

Easy to make a slide hammer. A 3 ft ready rod (1/2"? 5/8"?), a few nuts, some sort of clevis for your bolt and a suitable weight (20lb?) with a hole in it.
 
I've seen 2 of those replaced, both had developed pinholes which let saltwater into the concrete ballast that would then percolate out. On one of them they busted out the concrete ballast to get to the tube. The other they spent days trying to pull the tube out the back. They finally got it done. At one point they had a chain going from the tube to a forklift and would get a running start with the forklift.
Those who suggest a slide hammer etc are underestimating the amount of force that's required.
After seeing it done both ways even though it's a big project I'd vote for breaking out the concrete.
The other issue with trying to get it out he back is then what do you replace it with? A fiberglass tube of the same outside diameter, so it will fit in the hole, will have too small an ID for your cutless. If you break out the concrete you don't have this problem.
I think the cause of the leak is not that the shaft rubs on the tube rather it's corrosion causing pinholes.
 
Sean I'd be afraid of pulling it off the stands running from it with a forklift. I think the slide hammer maybe could work just because I was able to get it that far just hitting it with a standard claw hammer with limited swinging room. I'd hate to have to cut out my cabin floor to bust up the concrete.
I am too far into the project now to not follow through.
 
Great thread, lots of really good input. I agree the idea of drilling and putting a bolt through is likely to tear the end of the tube off, though that's how I remove my cutlass bearing with a slide hammer. I think because you were able to move it at all you are on the right track to keep sliding it out the back. It's too bad it's 6' long or you could saw through the tube and loosen it that way, but with that length there's no way... It would really suck to tear the tube in half partway out, pushing it back in and attempting to lubricate the tube might be a workable option. I'll be watching this thread!
 
In the picture provided, the tube looks to be made of bronze, not stainless and the wear is classic shaft rubbing through, not corrosion.
 
Yes the stainless tube was threaded into the back of the bronze piece in the picture, the rubbing/wear on the bronze piece also carried into and through the threaded end of the tube itself. Being that there was that damage I didn't want to worry about possibly unseen corrosion.
 
Just because the tube is stainless doesn't prevent you welding a cap on it for a
slide hammer attachment. TIG weld on a flat stainless plate with a threaded hole.
As you already noted, the good news is that you got it to move a few inches.
 
I like the cap and slide hammer idea. If you can't get the threads to work, you might be able to get one of these Victalic couplings to stick on there. It will come down to if the OD is similar enough to an Iron pipe size, and if the existing tube is stiff enough. You can put a Victaulic plug in the other side of the coupling, and drill a hole in the middle of it to attach a slide hammer. This stuff is available at commercial plumbing supply houses.
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