Filling Void in Rudder Shaft

[bornyesterday]

I remember reading of hollow steel rudders being filled with oil to avoid internal corrosion. This was mild steel not stainless, it was a very long time ago and I can't remember the source.
No idea whether this is still considered good practice, hope someone who knows will comment.

[Cheechako]

inject it full of axel grease!

[stillbuilding]

My Steelie has oil filled rudder. 60mm solid steel shaft


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[rognvald]

Minaret,
I read the data sheet about Chockfast( a superior epoxy) and they said the pour should be 2 1/2 inches. I guess multiple fills to allow the epoxy to kick would be the correct method. However, would you recommend filling the void or is the water retained from condensation not an issue? This can be easily resolved while the rudder is out of the boat and more difficult once installed. Also, are you aware of what was commonly used to fill the bottom of the rudder shaft on hollow rudder stocks during construction in the 90's?

[Pauls]

First of all, drilling a hole will function as a significant stress riser. It is a good generality that stress around the perimeter of a hole is 3 times the stress in the surrounding metal. If this rudder was designed to handle the stress it sees without any holes then you should not not assume that increasing stress is acceptable.

Just fill the hollow part of the tube with oil. It is an absolutely effective way to protect against corrosion. And it is free.

If you don't like the oil for some reason then another approach is to weld on a cap at the end of the shaft. This will seal the tube ID. With the oxygen available for corrosion limited to what is trapped inside the tube corrosion will be positively stopped.

[Jbingham]

The water in contract with metal can create corrosion over the years. Inspection every 10 years by dropping rudder and inspecting for corrosion a good idea. We are doing ours this week. Better to do once every 10 than watch as she sinks to the bottom... I'll find out the best solution when wear or damage is found Friday when I talk to our service gent. Hopefully it's for information only and not because I need the repair!!

[minaret]

Originally Posted by rognvald

Minaret,
I read the data sheet about Chockfast( a superior epoxy) and they said the pour should be 2 1/2 inches. I guess multiple fills to allow the epoxy to kick would be the correct method. However, would you recommend filling the void or is the water retained from condensation not an issue? This can be easily resolved while the rudder is out of the boat and more difficult once installed. Also, are you aware of what was commonly used to fill the bottom of the rudder shaft on hollow rudder stocks during construction in the 90's?

Left over shop resin, usually.


No corrosion yet, after how long? I wouldn't be too worried, but if I was trying to be thorough I might pour it. Wouldn't be at the top of my list, though.

[darylat8750]

I would put in enough Boshield T9 to coat it and call it good.

[minaret]

Originally Posted by Cheechako

inject it full of axel grease!

I like this for the quick and dirty solution. But only if you can cap it or plug it.