kev_rm
Senior Member
You can see my shaft zincs sitting right next to it in this picture.
Just had diver a week ago said "40%"..
Good excuse to put on the scuba gear.
I barely got to my engine zincs in time. No excuse really. 3 annodes, 2 in the after cooler and one in the heat exchanger. The lower aftercooler was down to 25% and fell apart as I removed it. The other two were OK.
Just had diver a week ago said "40%"..
Put a giant zinc ( or better yet, aluminum) anode on your transom and bond everything to it with shaft brushes etc. Then the rest of the zincs are not as critical.
Believe its 50% weight and not visible remains.
At my company, we use three criteria to determine whether or not to replace an anode:
1.- Is it less than 50% depleted? (based on overall remaining size)
2.- Are the attachment screw threads still completely covered by anode material?
3.- Are we confident the anode will still be providing protection until our next service?
If any of these conditions are not met, we replace the anode.
But I have seen some zincs that looked like new till you looked closely and saw how porous they looked and how light they were.
So I guess weight is important but surface area is more practical.
A porous or pitted zinc would have more surface area than a solid one, but less mass.
So which is it?
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Just messing with you.I wish I knew...
I change by gut....worked for me but have been looking at zincs for 50+ years.
The experts, if you can call them that, say weight of zinc involves longevity....the surface area involves ability to protect (ongoing).
Fstbottoms makes a lot of sense in there are several factors when to replace...just depends on you betteing how much anode is left in the alloy you have bolted or welded on and its ability to protect.
If you figure out the right answer...I am all ears....
Just messing with you.
But I hope no TFer runs out of air due to analysis- paralysis while diving on their anodes.
Once I make a decision to change mine, I do. If they look better or worse than the last periodicity, adjust accordingly for next time.
I check mine with a borescope from the dock.
I wonder why pro divers at docks do not get bothered/electrocuted from stray current??
Good - Lot less danger than diving at the dock having possible stray electrical current. With as many times and different areas they go in...I wonder why pro divers at docks do not get bothered/electrocuted from stray current?? Maybe some do.