Hi Kent, looks ugly. When your prop shaft zinks fell off did you replacen immediately. Also, the fact they just coroded around the stainless bolts could sugest limited contact with the prop. I have used cone prop zincs in the past and they corroded all over, certainly faster around the bolts. However for some years I have used shaft zincs betwen the prop and the c drive housing(i dont have line cutters) They have corroded relatively evenly.

Regards

Danny

SM 299

Ocean Pearl 

On 29 March 2020 at 08:32 "karkauai via Groups.Io" <karkauai@...> wrote:

Hi All,

I’m hauled out for bottom paint and servicing the Amel-supplied WOB and bow thruster seals.  It has been 4.3 years as I have had Island 44 on the bottom, and it lasts that long.  No water ingress and no oil loss.”, so I haven’t done the service until now.  Please see the pic of the WOB.  It is crumbling apart as if it were damaged by corrosion/electrolysis.  The hull potential has been perfect at -980mv every time I’ve checked it, and the rudder zincs have lasted almost a year with normal erosion.  I have used prop zincs on it since I had the prop shaft electrolysis a few years ago.  They have disappeared after a few months, mostly because they erode at the bolt hole edges and fall off, rather than completely erode away.

It’s going to be a bitch to get out, but bigger question is why did it corrode?  Any thoughts?  

Thanks in advance,
Kent
SM 243
Kristy