rudder shaft repair options

JimMoser · Feb 24, 2018

Not sure how to fix this, basically would like to clean up the area where the flax stuffing rides as it has some electrolysis corrosion, customer wanted me to weld it up and grind it down but I’m not interested in doing that and I don’t see a way of removing the shaft from the bronze spade, must be cast onto it ? Thinking of sleeving it either with a slip fit and JB weld or making a 3 inch long heat shrink with a collar like a speedisleeve. I am sure I could add 1/16 inch to the diameter and still get the packing in. Probably need to bore the ID for the fit and then turn it on an arbor for the OD. Or we could just JB the pitted area and stick it back in. I don’t see any way of removing this shaft so would need to build or buy two new rudders and I don’t think he is willing to do that at this time. Any ideas?

bhigdog · Feb 24, 2018

I'd bead blast it clean and soft solder a sleeve in place..........Bob

muckalee · Feb 24, 2018

The corrosion cracks may be much deeper than you realize. I see two possibilities. undercut the affected area 2 or 3 inches or some distance from the damage and make a split sleeve and braze to original shaft. Another is to cut the shaft a few inches from the rudder and fit a new shaft to the old one with a coupling and braze in place. If the shaft is large enough, you may make a stub and socket joint. I did not note the diameter of the shaft.

guest · Feb 24, 2018

This is one of those rare situations where I agree with the customer.

There's a mile of clearance between the packing gland and the rudder shaft. That's what the flax is for, and they normally drip a little anyway.

Grind out the crack, weld it up, and grind it somewhat smooth and somewhat round. Dynafiles work good for this. The new packing will take care of the rest.

Or JB weld it up and put it back together, he'll be doing it again in a couple years...

Bottom paint on the rudder makes me think he is running in salt water. There is plenty of room between the hull and the rudder blade- he should add a shaft zinc on the rudder shaft. And it wouldn't hurt to put a bonding wire to the packing gland just for good measure.

Tony Quiring · Feb 24, 2018

Look for an engine rebuilder.

They have crankshaft welders that can weld that right up then turn back to size.

Is there a sacrificial metal that can be added?

Sent from my SAMSUNG-SGH-I337Z using Tapatalk

Richard King · Feb 24, 2018

I would ask the customer to look at the options in writing and have them pick it. A replacement would be the best way. Have them sign off on a paper so your not liable if it breaks at sea and someone gets hurt.

Expect them to sue you if something happens. If you have a repair shop your obligated to repair it the right way and not a sub par way. Can't you call the boat mfg and get a price on new parts and how they would repair it?

jmead · Feb 24, 2018

I’d put in a few more minutes looking at pulling the shaft. A 60 ton or so Hollocylinder should pop that out cold in under a minute. If it’s brazed get it glowing around the shaft.
Regards,
John

LKeithR · Feb 25, 2018

jmead said:
I’d put in a few more minutes looking at pulling the shaft. A 60 ton or so Hollocylinder should pop that out cold in under a minute. If it’s brazed get it glowing around the shaft...

If you're talking about removing the shaft from the rudder plate I'd be very careful. I've seen numerous methods of locking the shaft to the plate; grooves or
pins in the shaft being the most common. Even if the shaft is just "cast in place" with no mechanical locking devices the rudder plate is likely a bronze
alloy of some sort and is quite possibly shrunk to a very tight fit. I've seen more than one attempt at removal end with a shattered rudder and a bent shaft.

There are quite a few places on the net that make replacement assemblies. Even if youcan't find an exact match they can be massaged to make them fit.
Might be a more viable option...

Peter from Holland · Feb 25, 2018

Put the shaft in a 3 jaw chuck with the rudder hanging out On low speed drill a centerhole in the rudder If that section is to thin weld, braze or solder it up a bit or bolt on some material
Now you can turn the damage down Weld it up Straigten it and turn it down You need a lathe that can handle the swing If you want to do a perfect job weld it up on all bearing positions and turn it down in one setup

Peter

jmead · Feb 25, 2018

LKeithR said:
If you're talking about removing the shaft from the rudder plate I'd be very careful. I've seen numerous methods of locking the shaft to the plate; grooves or
pins in the shaft being the most common. Even if the shaft is just "cast in place" with no mechanical locking devices the rudder plate is likely a bronze
alloy of some sort and is quite possibly shrunk to a very tight fit. I've seen more than one attempt at removal end with a shattered rudder and a bent shaft.

There are quite a few places on the net that make replacement assemblies. Even if youcan't find an exact match they can be massaged to make them fit.
Might be a more viable option...

Sure but admit it, using tons of pressure to pull a stuck shaft/javelin can be both satisfying and entertaining.

michiganbuck · Feb 25, 2018

Might you put in a steady. turn off what needed to prove there is no crack..then spray weld it to build up..then turn back to size...

LKeithR · Feb 25, 2018

jmead said:
Sure but admit it, using tons of pressure to pull a stuck shaft/javelin can be both satisfying and entertaining.

Yeah, especially if you watch someone else do it...

In situations like this I much prefer to be a spectator rather than a participant...

steve-l · Feb 25, 2018

I would be very skeptical of a repair at all. My fear is for what you cannot see. Fitting a bronze blade to a steel shaft in water is an invitation to electrolytic corrosion. This is an example of very poor engineering. You already see signs of crevis corrosion at the packing gland, that's a clue of what you may see at the bronze/stainless steel interface. The rudder blade and shaft should both be SS.

guest · Feb 25, 2018

^^^ Silicon Bronze and Stainless Steel are right next to each other on the nobility chart- they co-exist just fine in marine environments. We use bronze wheels on stainless shafts all the time. A simple shaft zinc is all that's needed. Bonding the hull penetration is also good practice.

The construction of the rudder is completely typical of boats that type and size, it's not a design deficiency. Practically all your competition ski boats and small inboards use this type of rudder.

You cannot press out that rudder shaft. The shaft is cast in place, and it's keyed or pinned inside the rudder blade. Could be a plate welded to the shaft, or any other of several ways to keep it in place, but it has something inside the rudder blade that will prevent it from pulling out.

Welding it up is perfectly reasonable. If boat owners threw away every part that ever corroded we would never use our boats. Ask any commercial vessel operator- you are repairing shit all the time.

steve-l · Feb 25, 2018

guest said:
^^^ Silicon Bronze and Stainless Steel are right next to each other on the nobility chart- they co-exist just fine in marine environments. We use bronze wheels on stainless shafts all the time. A simple shaft zinc is all that's needed. Bonding the hull penetration is also good practice.

The construction of the rudder is completely typical of boats that type and size, it's not a design deficiency. Practically all your competition ski boats and small inboards use this type of rudder.

You cannot press out that rudder shaft. The shaft is cast in place, and it's keyed or pinned inside the rudder blade. Could be a plate welded to the shaft, or any other of several ways to keep it in place, but it has something inside the rudder blade that will prevent it from pulling out.

Welding it up is perfectly reasonable. If boat owners threw away every part that ever corroded we would never use our boats. Ask any commercial vessel operator- you are repairing shit all the time.

Your response is typical of many folks that think they are correctly informed. they feel informed because Bill, who they respect, told them so. Yes I agree, bronze and stainless construction is done all the time. That doesn't make it correct. There is no such thing as a nobility chart, it's called the periodic table. It is from that we view nobility. The periodic table only identifies non-homogenic elements not alloys. Alloys are homogenous or mixtures of elements and any guess of where different alloys exist in relation to nobility is just a wild assed guess at best. Adding a sacrificial anode is only a Band-Aid to a bad engineering choice. Bronze and stainless steel are different and have different natural electric potentials. There will be electrolytic current between them in the presence of an electrolyte. Perhaps if these engineering errors were not regularly made, all those repairs those commercial guys perform would not have to be done in the first place.

guest · Feb 25, 2018

steve-l said:
Your response is typical of many folks that think they are correctly informed. they feel informed because Bill, who they respect, told them so.

You are free to believe whatever you wish. I am the son of a commercial fisherman, grew up on boats, and have owned, built, and operated them my whole life.

steve-l said:
Yes I agree, bronze and stainless construction is done all the time. That doesn't make it correct. There is no such thing as a nobility chart, it's called the periodic table. It is from that we view nobility. The periodic table only identifies non-homogenic elements not alloys. Alloys are homogenous or mixtures of elements and any guess of where different alloys exist in relation to nobility is just a wild assed guess at best.

There are numerous charts out there that we reference to select compatible metals. Here is an example:

012-Bi-Metallic_Corrosion_of_Commonly_Encountered_Materials.jpg

steve-l said:
Adding a sacrificial anode is only a Band-Aid to a bad engineering choice. Bronze and stainless steel are different and have different natural electric potentials. There will be electrolytic current between them in the presence of an electrolyte. Perhaps if these engineering errors were not regularly made, all those repairs those commercial guys perform would not have to be done in the first place.

Sure, we could build everything out of stainless steel, lol.

RC Mech · Feb 25, 2018

steve-l said:
Your response is typical of many folks that think they are correctly informed. they feel informed because Bill, who they respect, told them so. Yes I agree, bronze and stainless construction is done all the time. That doesn't make it correct. There is no such thing as a nobility chart, it's called the periodic table. It is from that we view nobility.

As noted above, there exist tables which depict likely galvanic interaction between disimilar metals. These interactions are well-known and well-studied in the literature. What the tirade against Bill has to do with this is beyond me.

steve-l said:
The periodic table only identifies non-homogenic elements not alloys. Alloys are homogenous or mixtures of elements and any guess of where different alloys exist in relation to nobility is just a wild assed guess at best.

No, the Periodic Table identifies elements which by definition are atomic, and arranges them by ionic radius, electronegativity, ion potential and atomic radius.. Alloys are heterogeneous compositions of elements- and a mixture by very definition is heterogeneous. Nobility is a coloquialism for unreactive, and though not what we chemists would seek to measure per-se, it is FAR from a “wild assed guess”.

steve-l said:
Adding a sacrificial anode is only a Band-Aid to a bad engineering choice. Bronze and stainless steel are different and have different natural electric potentials.

“Natural electric potential” is not a physical parameter. There is no such thing. There are redox potentials of various elements and mixtures of elements, which can be ascertained from the the electronegative ions in the proposed system (ie, the most reactive elements that compose the redox reaction that will take place preferentially).

steve-l said:
There will be electrolytic current between them in the presence of an electrolyte.

No, this system is galvanic, a redox reaction that is sponteneous and requires no outside energy to be introduced into the system.

keithmech · Feb 25, 2018

the problem with electrolysis is what you see on the surface
is not indicative of what is subsurface.Might be cheapest
/safest /easiest to just fab a new shaft /rudder out of s/s.
On the water do it right or walk away.

jmead · Feb 25, 2018

guest said:
^^^

You cannot press out that rudder shaft. The shaft is cast in place, and it's keyed or pinned inside the rudder blade. Could be a plate welded to the shaft, or any other of several ways to keep it in place, but it has something inside the rudder blade that will prevent it from pulling.

Well that’s a handy bit of info. I would not have thought anything more than a press fit or maybe open key way would be needed in a rudder that size.

Nice to learn something the easy way for once.

Jim Moser · Feb 25, 2018

thanks for the responses , I took the walk away advice, I did install ss zerk fittings in his stuffing boxes so he could pack grease under the packing, the shaft was 1-1/4 inch and I was curious about the construction , I wasn’t thinking of removing it and shure wouldn’t try to swing that thing in my lathe. They must just let the bronze solidify around the shaft and maybe some features in the shaft to insure no movement ? He will likely just blast it and JB weld it and keep it stuffed with grease , not perfect but nothing is in an old boat. Buck Algonquin still makes them if he needs to get a new one in the future.

rudder shaft repair options

Plastic

Stainless

Cast Iron

guest

Guest

Titanium

Diamond

Hot Rolled

Stainless

Diamond

Hot Rolled

Diamond

Stainless

Titanium

guest

Guest

Titanium

guest

Guest

Stainless

keithmech

Guest

Hot Rolled

Hot Rolled

Similar threads