Prop shaft zinc 29s

[Cruzerboy]

Has anyone experienced this issue? I've had two new prop shaft cone zincs installed (size F, one from Fisheries and one from the factory parts dept.) and in both cases the divers said the original and the two new zincs spun on the shaft, even after the retaining bolts were tightened snugly. Loose zincs are probably worse than no zincs--no firm electrical contact between the zinc and the boat metal. I'm in the process of installing a bonded shaft brush in the engine compartment just to be safe. Thoughts?

Tom
Life Savor
Seattle

 

[NorCal]

Hi Tom, I have the same problem on my 31. Except in my case the prop zinc just disappears.I put it on myself, tightened it up as tight as I felt comfortable doing and within a month it had disappeared. I am also looking to install a prop shaft brush. Hopefully will get done next week. Ranger Tugs is working with the manufacturer of the prop nut to try and get a better setup. What we have does not work well.

John

 

[Red Raven]

We have gone through three of these zincs in two years and have had significant rudder corrosion as a result. It is a poor design that has been around for many years (long before Ranger Tugs chose to use this option). There are various discussions and solutions regarding this on the site. Search for "prop zinc".

I chose to add a transom zinc over a shaft brush because we were getting more corrosion damage to the rudder than the prop and the rudder does not have a zinc (The factory did not recommend a rudder zinc for some reason unknown. Our new transom zinc is bonded to the rudder shaft inside the boat.

In my latest attempt to solve the prop zinc problem we "painted" the ends on the prop zinc with a felt pen to slow the shortening and maintain bolt tightness. Of course the zinc still needs to make contact with the shaft to add any value. Shims (pennies!) are used by some to maintain contact. Also be sure to use locktite on the threads so it doesn't just spin off (but if your bolt is tight and zinc is just loose instead of spinning off this will not help the problem). Our latest zinc is still there (installed in June). We'll see if it is still there when we pull out in October. I also added a galvanic isolator to deal with any potential hot marina issues.

Good luck!