Prop zincs

[Jrando305]

I have a 2018 C28 and I’m having a zinc issue. I returned from a 4 day cruise today and decided to check my prop zinc. It was installed app 6-8 weeks ago and I checked it prior to leaving and it appeared fine. Today when I checked, it was gone, the bolt and washer and what appeared to be a small piece of the zinc were still there. I buy my zincs from boat zinc.com. My thruster zincs are fine. I just seem to keep losing the prop zinc. Is there a difference in zinc from one manufacturer to another?

 

[lproulx]

I have had the same problem, and so have others. There is quite a bit of discussion in the archive messages. It centers around various kinds of thread locking products. I finally got pissed off and took a different approach. I bought a sort of plain collar (not oval) zinc intended to go right on the propeller shaft. Unfortunately there was too little exposed shaft for it to fit. Fortunately, I have a metal lathe and turned it down so when it was installed right up against the prop there was about 1/8 in clearance between the zinc and boat, enough to let water in to cool and lubricate the stern packing. You could probably do the same thing by doing some careful sawing on the zinc collar.

Larry

 

[BB marine]

There are a couple things that can go into the answer. First the thrusters are not bonded. The anodes only protect the small bronze thruster housing. The thruster anodes are aluminum not zinc. If you visited a transient slip with power at the dock and do not have a Galvanic isolator you may have had a neighbors boat that used your prop anode. Do you have anodes on the trim tabs ? What material anode are you using? If you don't have anodes on trim tabs it is recommended by Bennett. These anodes will work like the thrusters not bonded and only protecting the tabs. Do you have a divers anode on the transom ? What material anode is that?

You didn't loose your anode because of the bolt/washer coming loose and falling off. You lost it because it was doing what it is supposed to do. Yes anodes are not all created equal. I can't speak for Zinc boat .com . I have never used their product. If I was replacing anodes for outboards or stern drives I always used OEM anodes which were Aluminum. If I purchase aftermarket anodes I purchases Martyr brand anodes. I also do not use Zinc anodes.There are many articles written that state the Aluminum anode by weight can last 3 to 4 times longer than a Zinc anode. There is a catch, the weight of the aluminum is much less than the Zinc. Most articles state that the decay of the aluminum in the same dimensional size anode is slower than the zinc. Regardless of material your boat must be isolated from other boats around you. This is strictly my opinion and experience.

 

[Kaptajnen]

I installed a Shaft Brush that fits in the small space between the gearbox and the packing on our boat. It bonds the prop to the boat.

There is a photo in my album showing the installation. Below is a (failed) attempt to link to the photo.

/http://www.tugnuts.com/gallery2.php?g2_itemId=70070&g2_imageViewsIndex=1http://www.tugnuts.com/gallery2.php?g2_itemId=70070&g2_imageViewsIndex=1/img]

 

[jaredjensen]

Below is a (failed) attempt to link to the photo.

Here you go. =)

Kaptajnen, where'd you get that shaft brush? And do you also continue to use a prop zinc? I was planning to add a brush and an isolator because my prop zincs only last about 3 months, too.

 

[Kaptajnen]

Sorry I did not see your question until today.

Westmarine carries the Promariner Shaft Brush for $30.

I still use a Prop Zinc... but now it lasts a lot longer... so far 4 months