odd galvanic corrosion problem.

[Joef]

Men - had a small issue last fall that could have been much worse...

when i pulled the boat, i found that the zinc anodes on the shafts were completely gone (unusual...in past years, they were pretty bad, but always there). I found some pitting on the prop blades. The odd thing...the zincs in the engines, and the large zinc on the transom, and the zincs on the trim-tabs were all in good shape. (i should say "normal" for end of season).

My boat does not have any plastic "shaft savers" or other devices...just steel flange, bolted to steel flange.

Boat sat for several weeks late in the fall at an old dock(wife had our first baby in October...couldn't just leave to go fishin) ...and i'm suspicious that there was some bad stuff floating around that caused this...on the other hand, i did not leave the boat plugged into shore power.

Anyway - the damage to the props were "cosmetic" accorind to my prop guy and the shafts and the rest of the fittings looked good - but, i'm wondering why i had the issue with just the shaft zincs and not the others...and what can i do to make sure it doesn't happen again...and...is there some sort of test that can be done to check if the issue is somehow with my boat?

I've read over Cap't Pat's article...i'll double check the entire system...but...i'm stumped on why it only happned to the shafts (and my expensive props)

thoughts?

J

[CaptPatrick]

Joe,

It was probably an installation problem. Look at the inside of shaft zincs and you'll see a small copper colored ball bearing on each half. These bearings are what assure electrical contact with the shaft. If the zincs don't have this bearing, they are cheap imports. Use only Camp zincs throughout your system...

When installing shaft zincs, first clean the contact area of the shaft with a piece of 220 grit sand paper, making sure that the area is bright. wipe with either acetone or alcohol and install the zincs. Once the zincs are tight, use a mallet or light hammer to fully seat both halves & re-tighten. Two or three light to medium blows from the mallet or hammer on each half is sufficient.

Br,

Patrick

[Carl]

That's funny. I guess different areas have different thoughts about what is best. Around here Camp is considered to be "The Cheap Anode" and B&S are the best, no crappy little screws or copper buttons, just a real heavy duty hand cast Zinc Anode.

http://www.propfixer.com/bns_zinc_catalog.pdf

[CaptPatrick]

Around here Camp is considered to be "The Cheap Anode" and B&S are the best, no crappy little screws or copper buttons, just a real heavy duty hand cast Zinc Anode.

Carl,

Thanks for exposing us to the B&S zincs. Literature looks convincing for the most part.

As far as "crappy little screws or copper buttons" goes, I see no flaws there in regards to the Camp zincs... I've never seen any failure from the ss hex head machine screws that Camp uses, other than improper installation where the screws weren't fully tightened, allowing the zinc to slide down the shaft or fall off entirely. I can see that possibly the addition of copper ball on the Camp zincs may be necessary based on B&S' analogy of proper alloy & casting techniques, but I still don't consider Camp as an inferior zinc.

Unquestionably, alloy makes a difference & the cut rate Canadian zincs are an example of low quality alloy.

Br,

Patrick

[mike ohlstein]

B&S are nice guys to work with too. They do all of my prop work and supply all of my zinc.

[Carl]

no crappy little screws or copper buttons

Capt Pat,

Sorry, I can see how that may sound. My custmers are the ones who refer to the Camps that way, I hear Camp Anode and I automatically think of a bunch of customers that will "just go off on me" when I ask them if they want Camp or B&S Anodes. That is the one line that always sticks in my head. I sell both here as the B&S are considerable more expensive, and many will not buy them.

The screws are one or two sizes up on the B&S anodes, once you get used to putting them on you wind up twisting the Camp screw heads off when trying to tighten them up in a similar fashion.

I'm not sure where I stand on the copper button, I like the idea, but have been led to believe it is more of a gimick, just clean up shaft like you said and tighten down.

I really just find it funny how in different areas we think different brands are just better. And most important, like you said Stay Clear of the imports.

[Dug]

I am a big fan of Godfrey zincs. They have a bronze core ring that completely surrounds the shaft and the fasteners attach through that ring. The zinc cannot loosen or fall off. I have used them now for about 5 years and think they are great.

Last year I went from 2 per shaft to 1 as I don't need the two any longer since they don't loosen and slip or fall off. I get a full life span out of the one on each side. Great and a good savings to boot!

They can be bought from H&H as well as NE propellor up in our neck of the woods.

I have also heard great things about Camp, but they have the ability to loosen unlike the Godfreys.

Dug