White Deposit On Rudder Shaft

[zstine]

Posting for a friend...


Hi All,

I posed this question last fall [on a Tartan Forum] and didn’t get any responses. I’ve now asked my boatyard and reached out to a couple prop and rudder shops, and no one seems to know what this is around my rudder shaft. It’s not salty and has the consistency of paste or almost grease. I’ve never seen it there until winterizing this season.

My biggest concern is electrolytic corrosion from a stray current on my dc system. I’m likely being paranoid, but want to make sure. I’m never on shore power and float on a mooring, so there isn’t any ac power around me. The guys at jefa suggested limestone, which has me confused. Just to make sure I understand electrolytic corrosion, if I did have a stray current, wouldn’t my zincs on the shaft and prop be severely worn if it was then impacting my rudder stock?

Also, for a Tartan 40, is there any maintenance that needs to be done on the stern tube. Some boats have grease fittings. I don’t see any on the Tartan 40.

Thanks,
Garrett

[MicHughV]

My 2 guesses...

1) There is usually a bearing there somewhere, could it be residue from that..???

2) I'm sure you've seen packing flax for engine prop shafts.....usually a ring of some material impregnated with a some or other material...but these days it can also be found as a teflon wax......something has to keep the water from spilling out of the top.

That green looking ring appears to come apart, I'm not familiar with it, but that looks like it comes apart and then gets packed with that teflon material...???

[MicHughV]

your question regarding the stern tube needs some clarifation.....these too, come apart, leaving room to insert either the old style package flax...or the newer teflon material.

[Cheechako]

Originally Posted by zstine

Posting for a friend...


Hi All,

I posed this question last fall [on a Tartan Forum] and didn’t get any responses. I’ve now asked my boatyard and reached out to a couple prop and rudder shops, and no one seems to know what this is around my rudder shaft. It’s not salty and has the consistency of paste or almost grease. I’ve never seen it there until winterizing this season.

My biggest concern is electrolytic corrosion from a stray current on my dc system. I’m likely being paranoid, but want to make sure. I’m never on shore power and float on a mooring, so there isn’t any ac power around me. The guys at jefa suggested limestone, which has me confused. Just to make sure I understand electrolytic corrosion, if I did have a stray current, wouldn’t my zincs on the shaft and prop be severely worn if it was then impacting my rudder stock?

Also, for a Tartan 40, is there any maintenance that needs to be done on the stern tube. Some boats have grease fittings. I don’t see any on the Tartan 40.

Thanks,
Garrett

SS shaft? Is that an aluminum housing going to the cockpit floor surrounding the rudder shaft?? Bronze gland, and.... is that a piece of aluminum also there? A yellowish nylon ring? I cant really tell. Is the rudder shaft in that pic or is that a housing around it?

The rudder shaft isn't aluminum is it?
Is it white corrosion off the aluminum?
Is there packing? Maybe it's Teflon packing residue?

[MicHughV]

I don't think I've ever come across a rudder shaft made out of aluminum...although it sure looks like it.

The plate above the post, appears to be the rudder arm???....with what looks like a stainless steel rod to the left of it....hydraulic steering arm ???

We never get enuff info from these CF " whodunnit's " so it becomes a bit of a guessing game...

In that vein...the green rings appear to be a rudder "Stuffing box " of some kind, I see a bolt on the side of it, which seems to indicate it comes apart....and gets filled with the teflon stuffing material ???

The Tartan 40 is an old boat, can't remember the last time I saw one..

Here is an excerpt from the Tartan 40 website..



There have been a number of problems with the Tartan Ten over the years. Tartan Marine generally acted responsibly in correcting them. The worst problems occurred in the first 100 boats. For example, the original hollow stainless steel rudder posts were too light and bent too easily. According to Tartan, every boat with that type of rudder post was located and repaired by inserting a second post inside the original one.'

[MicHughV]

so it seems that what we are seeing is a hollow rudder post, with another post stuck in it...the pic certainly suggests so....I'm definitely leaning towards the "Teflon" probability.

If the rudder post is a bit sloppy inside that upper bearing it can pump the teflon up....

my sleuthing for the day......

[amarinesurveyor]

Salt crystals

[MicHughV]

the OP has stated it is not salty....presumably he tasted it to say that ???

[GLH71]

Hi All,

Thanks to zstine for having the wisdom to ask this group, and thanks to all of you for your thoughtful replies. I am the owner of the Tartan 40 and suspect rudder post in question. To clarify and confirm a few things… the very top of the picture shows the quadrant and a rod for the autopilot. The quadrant is attached to the rudder post which slides into a separate collar. I believe the rudder post is stainless (picture attached). It is bolted into that collar and the collar spins with the rudder. It looks to me like whatever the white stuff is, it’s coming up out of the tube and falling down onto the nylon/plastic ring and stuffing box… If not corrosion, I’m assuming it’s some sort of bearing material or packing material as suggested by you all. I will start by opening the stuffing box. If that doesn’t yield an obvious solution, I assume I will have to have the boat lifted and the the rudder dropped.

I guess I was hoping someone would tell me it’s something I don’t need to be concerned about and I wouldn’t have another winter project to add to the list.

Thanks to all of you for your helpful suggestions.

[wingssail]

Originally Posted by MicHughV

I don't think I've ever come across a rudder shaft made out of aluminum...although it sure looks like it...

Our rudder post is aluminum. (approx 5" diameter tube with 1" wall thickness). It is not common but our manufacturer used these.

We do not have this white paste on our rudder post however but we have it on our aluminum mast step where it sits on the fiberglass floors. I am sure it is the result of some kind of corrosion or electrolysis.

I too would like to know what it is.

[Orion Jim]

My guess is that it is grease. The OP states it has the consistency of paste or grease. If the doubts about whether it is grease or not are keeping you awake at night there is a solution.
https://www.fluidlife.com/services/l...ease-analysis/

[MicHughV]

it's a boat y'know...all "easy" problems usually take a lot of $$$ to fix...

[knotnline]

I owned a Tartan, 2004 model, that resembled that .
It had a 4” dia rudder shaft, 1/2” wall thickness tube, 304 SS.
It had an aluminum sleeve locked onto the shaft with 3 studs in holes tapped into rudder shaft.
That Al sleeve rode on a plastic ring which sat on a bronze stuffing box.
The stuffing box was held on top of the fibreglass stub with 3 bolts.
The upper part of the stuffing box was fastened to the lower and held the packing in place.
It looked like yours and Had the same crystals deposited. I just assumed it was salt as there was always some seepage through the packing if there was any real wave action.
It was all able to be dismantled if you blocked the rudder from below or hung from cockpit floor. You can probably clean it up and replace packing but obviously need to drop the rudder a bit to pull the bearing ring off.

If you’re at that point the lower bearing could use a good look too as it’s likely worn.

Hope this helps

[GLH71]

Thanks for the feedback. That sounds like what I will need to do. I asked Chris Ranney over at Tartan how it’s all assembled and he just sent me this photo with labels. It’s exactly as you describe it. The retention collar spins around on that delrin washer so that the collar doesn’t destroy the stuffing box. I will need to block the rudder slack the steering cables, and disconnect the autopilot arm so that I can lift that collar and check the stuffing box. I don’t have clearance under the boat to get the rudder completely off to check the bearing. I may need to wait until the yard picks her up in the spring.

Thanks again to everyone who took the time to consider and respond. The sailing community always impresses me with their willingness to help.

Garrett

[captstu]

The Edison quadrant on my old Pearson 36 was aluminum and the rudder post was stainless. Eventually the white greasy power was found to be the product of electrolytic corrosion of the quadrant - when it failed.

Stainless erodes nearby aluminum - think aluminum anodes used instead of zinc in some installations. That was clearly what happened to me.

I purchased a new quadrant and painted it with several coats of paint/sealant. After a few more years, the products of galvanic corrosion had not reappeared.

The same problem happens when you use stainless attachments in an aluminum mast. Unless you carefully seal the bolt holes during the attachment process, the stainless eventually causes sacrificial corrosion of the aluminum.