Patching a stern tube

Now that I can see the inside of the stern tube on my Albin 36, it looks like there are 3 places that corrosion has eaten through the stainless. They are all on the bottom of the tube and look to be about 2” long by 1” wide. From seeing a tube that had been removed from another Albin 36 it looks like Swiss cheese. My plan is to get a syringe with a long spout and try to inject epoxy over the area. There is no way I would attempt to replace the tube.

Any other ideas?

meridian said:

Now that I can see the inside of the stern tube on my Albin 36, it looks like there are 3 places that corrosion has eaten through the stainless. They are all on the bottom of the tube and look to be about 2” long by 1” wide. From seeing a tube that had been removed from another Albin 36 it looks like Swiss cheese. My plan is to get a syringe with a long spout and try to inject epoxy over the area. There is no way I would attempt to replace the tube.

Any other ideas?

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The Eagle tube has some holes in it but it’s incased in concrete so it does not matter. If concerned I would slide another thin wall tube inside the old, and have a new narrow shaft made out of better SS than what the present shaft is made of. Not all SS is the same.

You can try what you are doing but make sure its bone dry, any moister will cause it to fail. So is the tube leaking and/or encased? But doing something is better than doing nothing?

You might also want to check how straight the shaft is as SS/metal will sag over time if stopped in the same position. We straight thousand of shaft per year so don’t let them tell you, you need a new shaft. if the shaft needs straightening I would look for a commercial shop. I had the Eagle shaft straighten as it had a sag in it, took 30 minutes to straighten.

I think you will waste time and epoxy trying to inject it with a syringe.

Look at this as one alternative:
http://www.nuflowtech.com/products.aspx
My own preference, and perhaps a better DIY method, is to use this:
http://stevensproducts.net/composite.htm
as a thin liner if you have adequate shaft clearance. Thoroughly clean and prep the interior of the stern tube and coat it and the tube with expoxy or something like 5200.
Fabricate a tool that looks like a short spool with an OD the same as the ID of your existing tube. The distance between the two outer ends need only be a half inch or so, it will look like a piston with a wide ring groove about halfway along its length. There should be a drilled port connecting the outside of one end of the spool with the center of the spool. Attach a flexible tube to the outside of that. It will be used to deliver epoxy or 5200. Attach a rod to the center of the spool like a piston rod on a hydraulic cylinder so that you can move the spool in and out along the length of the stern tube while pumping epoxy or 5200 in with a caulking gun and refillable cartrige. Do this slowly and allow all the holes and voids behind them to fill. When you pull it out the tube should have a smooth surface and be ready for the thin wall liner that has an OD very slightly less than the tube ID, you are looking for a "clearance fit" or one that allows very easy sliding in and out before applying the adhesive.
I have not done this on a stern tube but have done it to repair otherwise unreachable and unrepairable piping until a shipyard could crop out and replace the pipe. The repair would have lasted for years but was not a "class approved" technique for permanent repair otherwise it could have stayed.

If you can all the way around it, I would wrap it with fiberglass cloth and epoxy resin

meridian said:

Now that I can see the inside of the stern tube on my Albin 36, it looks like there are 3 places that corrosion has eaten through the stainless. There is no way I would attempt to replace the tube.

Click to expand...

I'm curious why you would not attempt to replace the entire tube.
Esp since I also have an Albin and may run into the same issue some day.

Very labor intensive since it is most likly buried in cement. Iv'e heard in the area of 10k+ for a yard to do it.

jleonard said:

I'm curious why you would not attempt to replace the entire tube.
Esp since I also have an Albin and may run into the same issue some day.

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it allows water to seep into the hollow keel....

I may have the same problem but was advised by a marina that pulled a 36 Albins tube that pulling the tube was worse than giving birth.

RickB's suggestion is about the same as I was thinking....there's a thousand ways to do it...it's just what will actually work and be easy enough to do.

I think I'll just live with it.

On my 34' MT although it was set in stone and resin It really was not that big of a deal to remove About 40 min with a hammer and chisel was all it took

Dut to built-in cabintry in the aft cabin, I can't get to the entire length that has to be removed

Guys, here's a picture that shows my hollow keel. About 6" deep by 3" wide. Should I fill it with concrete or.... have some lead cast to the exact shape in say 300 lb. units and put them in various places along the length to level the waterline where needed? Or just leave it empty.

Why do you feel the need to fill it with anything?

I don't neccessarily but this is my first trawler, all other boats were sportfish planing hulls and I've been reading alot about ballast in trawler keels. Another 42' Bristol named Moose has 3000 lbs. of lead pigs in his bottom, says its a better ride. That's why I'm asking here...

How does the weight of your new engine compare to old? IF you want more weight, I'd stay away from concrete and go with lead weights that allows your bilge to stay dry and you can get at any water if need be.

The weight will be very close if not more. I have heard about the concrete horror stories and dont want that so I think casting lead to the exact shape and size of the keel; maybe two or three say 2 foot long each spaced evenly along the keel length, and moveable so to balance the waterline. I would cast in lifting eyes to be able to move them forward and aft. Naval architechture, weight and balance, righting moments....I just want the boat to ride nice! lol

stevensibs said:

I just want the boat to ride nice!

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I guess you need to define "nice."

Do you want a fast roll or a slow roll?

stevensibs said:

The weight will be very close if not more. I have heard about the concrete horror stories and dont want that so I think casting lead to the exact shape and size of the keel; maybe two or three say 2 foot long each spaced evenly along the keel length, and moveable so to balance the waterline. I would cast in lifting eyes to be able to move them forward and aft. Naval architechture, weight and balance, righting moments....I just want the boat to ride nice! lol

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Fill the keel with lead pigs or lead shot. When you get her sitting the way you want, pour in several gallons of resin and add a little glass fiber to tie it together.

slow roll is what the boat is designed to give. And I think I'm going to go with the lead.

stevensibs said:

slow roll is what the boat is designed to give.

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That is why the keel is empty.

stevensibs said:

slow roll is what the boat is designed to give. And I think I'm going to go with the lead.

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We're 42' with 39' 2" of water line. If I added another 3,000 lbs, that would lower the water line 1.5". That would also mean I would have to raise the water line and re-paint the boot stripe.

sounds like someone should stop listening to many wannabe NA's on internet forums and rethink altering his boat based on some real expert input.

The OP might find it interesting to calculate the power (fuel/money) it takes to accelerate 3000 lbs to cruising speed and keep it moving for an hour.

I would love to know how the boat motion was initially and how much 3000 lbs of lead would really change it that much. And if it did, in what way other than making the roll snappier, but how much?

Without a stability test and calculations for adding weight...I would be very hesitant to go on some other boater's word (unless they were a very well established NA) or had a boat EXACTLY the same and set up the same and had ridden it many times in many conditions.