Corrosion on prop shaft

[thomcat]

I recently bought a Catalina 27 that the previous owner hadn't used in 2 years and found pretty intense green-powdery corrosion on the prop shaft (picture attached). The transmission casing (slightly showing in the picture) seems to be abnormally rusted also. I haven't had had the chance to check the propeller or zinc yet, but that is my next priority after maintenance the engine, transmission, and 12v systems. Is the pictured corrosion something serious to worry about, a mild sign of neglect, or am I worrying too much?

[Pete7]

Lots of neglect, but it can be cleaned up. Willing to guess the packing gland needs new stuffing packing too. If the boat is coming out, you can do all this in slow time and make a good job of it.

[bil56]

yes, just a water leak,
packing needs new stuffing

[boatpoker]

The white powder is from your stuffing box which is bronze, this is harmless residue from the chlorine / metal reaction ... Clean and forget.

Depending on how long that has been in contact with the shaft you may have a real issue with corrosion of the shaft. If your shaft is stainless steel, be aware that ss corrodes in the absence of oxygen. That damp powder sitting on your shaft for months or years could have corroded the shaft.

Clean it up and take a close look at the shaft.

[MicHughV]

it looks ugly for sure....but stuffing gland and shaft will clean up and look like new..just needs some elbow grease, wire brush, 400 grit on shaft, and a light coat of WD40 oughta do the trick.
besides the new stuffing material, I'd change out these hose clamps as well.
The transmission much the same, a good work over with a wire brush to clean the surface rust and some WD40 for protection.
You can change the stuffing packing material with the boat in the water ,but if you are planning on buying this boat it should come out of the water for a thorough inspection.

Last, but not least clean up the bilge area under the shaft and under the engine. Having a clean bilge is usually a good indicator to show drips, oil leaks, etc..

[boatpoker]

Originally Posted by MicHughV

..just needs some elbow grease, wire brush, 400 grit on shaft,

Do not use a steel wire brush or sand paper with metal particles, you could cause corrosion.

[thomcat]

Thanks for all the above advice and information! The corrosion itself sounds less serious than I was imagining. When I take her out of the water, I'll get it cleaned up and new packing in the stuffing box.

I've noticed another problem though: the prop shaft doesn't turn by hand when the transmission is in neutral. Could this have to do with the stuffing box being too tight or the amount of corrosion limiting the movement of the prop shaft? I haven't ruled out the transmission being the problem, but I want to rule out the most visually obvious factor before I consider that.

[boatpoker]

Originally Posted by thomcat

Thanks for all the above advice and information! The corrosion itself sounds less serious than I was imagining. When I take her out of the water, I'll get it cleaned up and new packing in the stuffing box.

I've noticed another problem though: the prop shaft doesn't turn by hand when the transmission is in neutral. Could this have to do with the stuffing box being too tight or the amount of corrosion limiting the movement of the prop shaft? I haven't ruled out the transmission being the problem, but I want to rule out the most visually obvious factor before I consider that.

Possibly but more likely misalignment.

[MicHughV]

Certainly, judging by the amount of visible corrosion on the shaft, the stuffing box might be equally frozen up.

You'll have to tackle this one item at a time.
#1, clean the shaft and stuffing gland.
#2, insert new stuffing gland material.
# 3, try to rotate shaft.

If shaft still doesn't want to rotate, it will be time to check the cutlass bearing on prop shaft on the bottom of the boat. See if there are any issues here, and if the cutlass bearing needs to be replaced.

Finally, if the shaft won't rotate, the obvious next step would be to check the transmission.
Firstly, see if there is any transmission oil visible. Check to see if transmission is in "nuetral".

You can separate the shaft flange from the engine flange to isolate the problem, if you can get those bolts loose.

With the shaft loose, will the shaft rotate, if so, the culprit will be the transmission.

But could also be other things...engine has seized up, etc.

Just tackle the issues one at a time.

Misalignment is always a concern, but is simple part of the puzzle. Just another boz to be checked.

[gonesail]

you'll never get the shaft off that coupler. maybe check the bolts at the transmission and put some penetrating oil on them. if they are rusted .. try to replace.

[MicHughV]

True, the shaft may prove to be impossible to remove from the flange, without heat, etc, but the two flanges should come apart, difficult sometimes with rusty flanges, but a little applied coercion usually does the trick.

[Pete7]

Originally Posted by MicHughV

True, the shaft may prove to be impossible to remove from the flange, without heat, etc, but the two flanges should come apart, difficult sometimes with rusty flanges, but a little applied coercion usually does the trick.

Agreed, soak for a week in penetrating oil rotating to get to both side of each screw and then use an impact wrench with good quality hex or sockets. Worse case is an angle grinder and cut it off.

Pete