Calcium build up between prop shaft and cutlass bearing

[djc]

Dose anyone have a solution to stopping or reducing the build up of calcium between the cutlass bearing and the prop shaft at that point only . I fitted a new cutlass bearing only 6 months ago and the prop shaft was totaly clean , when i came to with draw the shaft last week , the shaft its self was so gummed up with calcium build up , i didnt think it was going to come out.
Set up ; Cutlass bearing screwed into a 1/2 mtr long stern tube with a PSS shaft seal.


The shaft / bearing also makes a groning noise for about 30 seconds after sitting on mooring for a time. after that first use its fine .

Any ideas ...

 

[bluedragon]

Is it calcium? I used to get a hard white deposit on a bronze prop and around the stern tube. I put it down to an over-active anode, but not sure why I reached this conclusion at the time?

 

[Skysail]

could be small crustacea? I think I have seen this mentioned elsewhere.
.

 

[Neil_Y]

If it is crustacean then buy a bearing resistant to marine growth and one that helps clean growth off the shaft.

 

[djc]

The build up is like a smooth type of hard scale , scrapes off with a knife will try to attach a photo not sure if that will work .

 

[Ruffles]

I have the same problem. I seem to change the bearing every two years. I reckon frequent use is the only answer. I get an even layer of calcification over the whole shaft, not just under the bearing. And I don't use a shaft anode so I don't think that's the cause.

Plus point is that I'm now a dab hand at changing bearings without removing the shaft.

 

[malcp]

Yes, I get this too. I clean it off using kettle descaler and wire wool. Kettle descaler softens it nicely after it's finished fizzing.