Anode replacement A25

[Sunsetrider]

One of the many maintenance jobs I need to attend to before setting off into the salt water adventure - anode replacement. Where to get, what kind, and how to remove and replace. Advice needed!

[WillieC]

BoatZincs is good. I stumbled into a zinc sale at Fisheries Supply in Seattle and got a good price, delivered to my door. Buy enough and the shipping is free. I think the sale is in spring.

Saltwater anode will be zinc, by the way. I should call them anodes, but I don't.
First, what shaft do you have? Mine is 30mm. Don't fool around and try to make an SAE sized zinc fit. Personally, I like the Martyr line. Serious hex key bolts, none of this straight slotted screwdriver nonsense.

Your set up looks a lot like mine with the handy-dandy built-in prop remover nut on the backside of the prop. Very nice. Mine does not have the big washer there, like yours. I try to leave at least a quarter inch breathing room off the end of the cutlaeiou(and sometimes y)ss bearing. That water has to move some, but not a lot. If you need more room, you can trim the cutlass a bit, looks like you have plenty hanging out. Some folk pay more for skinnier anodes, or take them to machine shops to be thinned up. Pfft.
Buy stock, make them work.

They come off pretty easy and they break easy if they don't. Don't hurt the prop. Clean the shaft with a scraper, wirebrush, pocket knife, and slap the new one on. Most new zincs have the little copper nibs inside them to ensure good electrical contact, which can be easily checked with a VOM. I snug mine, spin them a little, then tighten them evenly. Don't let one side get ahead of the other. Careful, careful. They can break. One poster somewhere suggested whacking them with a hammer. I guess I took him literally and proceeded to break a brand new zinc. Fortunately, it was one of those straight slotted POSs.

Then keep an eye on them. How long they last is subject to a million variables, but they are cheap protection, even if they are not free. I probably wait too long to change mine, but at some point, you don't want them messing up the prop when they let go. Last summer I tried hanging an extra zinc over the side when at marinas. The inboard end simply clips onto the shaft under the floor boards at the coupling. I have heard too many horror stories, so I thought I was being smart. I even kept a log of the different voltages I found at the various marinas. Then somehow I managed to fake myself out (imagine that) and started recording ohms instead of volts and got completely lost. My over the side zinc was the one I broke when I whacked it. dkirsop writes about the over the side zinc somewhere. Just make sure to unhook it from the shaft before you fire up. Whenever anything is amiss or in process or a valve is closed or whatever...I stick a red twist tie in my starter switch and do not remove it until I have checked with the Starfleet Commander. Just for a double check. I also tell her when and why I stick it in the switch. Best to keep her involved and helpful when I miss something.

Mine also has one on the skeg shaft. I just broke my own rule and use an 1-3/8" on it, not metric. That size works fine for me. This zinc will last for years, so apparently not much is going on with it. Maybe too much all the same metal in the circuit. It, too, is now the low point on the boat (using a donut style, not the fancy dan bullet style). Ask me how I know. Still working on this trailering thing and manage to get in trouble too often. It sounds a whole lot worse than it should when it hits pavement, but no serious damage. Consider it a curb feeler and never try to use it.

Easy, peasy. Good luck!

[dkirsop]

Richard's posting covers most of the basics. Keep in mind as you head south that warmer water and brackish water will increase the rate of anodic corrosion so be sure to check your anodes from time to time. The lower strut is 38mm if I remember right which is very close to 1-3/8. We are supposed to be a metric country and recently I have been able to source 38mm from the local shops. I usually keep a couple of spares on hand and check things out whenever I have the boat on the trailer.

Using an over-side-anode, also known as a Guppy, does help reduce zinc loss. I only use it when tied up for more than a couple of days..

[WillieC]

My calculations show 35mm equal 1.377952756 inches. A hair over 1-3/8". But who's counting. (I am! HA!)

(Dave, I do hope we can meet up this summer on our way north. We'll have much to discuss. And thanks for all your good input!)

BTW and way off topic. I have seen an A25 for sale on some yahoo site for $1000 and that is because the trailer comes with it. I don't have access to yahoo so I can't verify. Anyone seen it?

[Sunsetrider]

Thanks guys. So I’ll shop locally for a zinc zinc. Don’t know why I gave my micrometer to my son when downsizing.

[WillieC]

Tell me about it. My dad, a machinist from the olden days, had a full set of zero to six inch Starrett micrometers and calibration blocks and the full set of inside mics, to boot. And a billion other good tools. I was busy raising the boys and other hard stuff as my dad was going downhill, so I wasn't paying much attention. Who knew? What was left in the shop was a pegboard rack of bent and rusty screwdrivers my mother couldn't even give away and I manage to find use for still.

But, years ago, I had a project that I needed the zero to one mic, and I never returned it. He never missed it and I still have it. Not long ago I bought a cheapo digital caliper that is close enough for everything I will ever hope to do. But I miss that old set of mics. Given the strained relationships between fathers and sons of our generation, I find I miss the old man, too. I often feel, in a good way, his presence when I putter over there. Maybe I miss that most of all, something we shared so little of in the short time we had. Happy birthday, dad.

[DesertAlbin736]

As always, interesting discussion guys!

Guess I'd have to go with one of those zincs that go on the prop nut, since there's almost no room between the nut in front of the prop and the cutlass bearing. I have one of those collar zincs on the rudder support/skeg pipe which probably doesn't much of anything for the prop. Haven't given it much thought since the boat spends 99.5% of the time out of the water sitting on the trailer. Besides which, other than coastal cruises it's in fresh water for 24 to 48 hours at a time one or twice a month during the fall/winter/spring season. So what's my risk exposure being in salt water for 6 to 8 weeks at a time?

DSCN3631crop.jpg

Should I look into one of these? I think there's enough space ahead of the rudder for this? The attaching machine screw does have Allen wrench head.

propeller-nut-installed.jpg

http://www.boatzincs.com/prop_nut_specs ... RQEALw_wcB

[Sunsetrider]

I wonder if that prop nut zinc might be the way to go, and just leave the donut zinc in place as it is.
Oddly, that deteriorated anode in my pic appeared to be unaffected (since the boat was purchased 4 years ago) until this past season, despite being in fresh water all summer. Perhaps spending so much time at the marina dock last summer accelerated the process, surrounded by all that shore power.

[Sunsetrider]

Doing a little research, it seems zinc is only recommended for salt, magnesium for fresh, and aluminum seems to have a wider set of acceptable conditions, including mostly brackish and salt. Some tables also include fresh for aluminum. Based on that, it would seem I should be considering an aluminum anode.

[WillieC]

DA, looks like your bullet zinc is 3.2" long. Looks like you might have enough. I would not forego installing it. Mine shows significant loss in that amount of time in the water with no marinas within three miles.

I've never messed with aluminum anodes, though I have read the same info, Sunsetrider. Question would be availability given your metric(?) shaft. Certainly cheaper to ship.

[Sunsetrider]

My local shop carries this:

https://www.marineoutfitters.ca/mobile/ ... t=44789853#

It might fit

[WillieC]

Careful. It is all about the thread size on your shaft. Maybe pop the nut off and take it to the shop.

AND, the clearance to the rudder. DA Steve looks like he has room. Yours may not, especially since you already have the donut fitted on the front of the prop.

[Sunsetrider]

it looks like the anode slides over the replacement nut system reused by the hex bolt. So as long as the replacement nut fits one may not need any additional room on the end of the shaft.

[LopezMike]

I'm a little startled to hear that a sacrificial anode is needed in fresh water. The conductivity is pretty low. Live and learn.

[ssrig]

Hey WillieC, I dont think there is a "Handy Dandy" nut in front of the prop, I see what looks like a rope slicer and a zinc ahead of that but zooming in it gets fuzzy??

Also the rear prop nut with the cotter pin through the most aft locking nut is interesting.