Shaft Anode Replacement Video

[fstbttms]

For you hull cleaners out there...

 

[Sekeli]

Does it make any difference whether you position the anodes close or further apart? I have always spread them out evenly on the shaft. Have you seen any changes in the way they corrode or maybe even protect?

 

[cool_hardware52]

Does it make any difference whether you position the anodes close or further apart? I have always spread them out evenly on the shaft. Have you seen any changes in the way they corrode or maybe even protect?

I'd expect zero difference in corrosion protection as a result of different spacing. I've changed 100's of these myself. Keep in mind the vessel's main zinc, typically a 6 x 12 x 1/2 thick plate, functions via a bonding wire.....

Brings back memories.

Tobin

 

[Sekeli]

Not every boat has a divers dream style plate. Most sailboats only have shafts anodes.

I've heard many things from the 'electolysis experts' Marine Electricians and others that hold workshops and what not who have also said things like...aluminum corrodes slower than zinc, which is true for the puget sound.

If there's a "hot" boat in a marina, nearby boats can be affected, which I have dealt with first hand.

They have also said hot boats in freshwater marinas provide a huge risk of electrocution to divers. I and many others have been in these environments with hot boats and haven't experienced anything out of the ordinary.

They're obviously not always right about anything but at the time it made sense and it's just something I've always done.

 

[cool_hardware52]

Not every boat has a divers dream style plate. Most sailboats only have shafts anodes.

I've heard many things from the 'electolysis experts' Marine Electricians and others that hold workshops and what not who have also said things like...aluminum corrodes slower than zinc, which is true for the puget sound.

If there's a "hot" boat in a marina, nearby boats can be affected, which I have dealt with first hand.

They have also said hot boats in freshwater marinas provide a huge risk of electrocution to divers. I and many others have been in these environments with hot boats and haven't experienced anything out of the ordinary.

They're obviously not always right about anything but at the time it made sense and it's just something I've always done.

Active cathotic protection will "eat" everything nearby.

Aluminum is "more noble" than Zinc, pretty much everywhere, not just in Puget Sound....

Tobin

 

[Sekeli]

So what is the purpose of an aluminum anode? I have records of boats that I have switched over from zinc to aluminum, they typically lasted 25% longer.

Magnesium is "less noble' than zinc but it doesn't corrode well in a saltwater environment.

 

[Sekeli]

By "corrode well" I mean efficiently, I've seen electrolysis and corrosion on running gear because some diver put magnesium on and they were never replaced because they corroded from the inside out and no one thought to replace them. They weren't protecting anything for months.

 

[cool_hardware52]

So what is the purpose of an aluminum anode? I have records of boats that I have switched over from zinc to aluminum, they typically lasted 25% longer.

Magnesium is "less noble' than zinc but it doesn't corrode well in a saltwater environment.

I'd be a bit concerned if the "sacrificial anodes" were lasting longer. That suggests something else is being consumed.

I always used zinc and nothing but zinc. I used to cast my own plates and "plug" zincs used in cooling systems, but I always used commercial shaft zincs.

Tobin

 

[fstbttms]

Does it make any difference whether you position the anodes close or further apart? I have always spread them out evenly on the shaft. Have you seen any changes in the way they corrode or maybe even protect?

Together, apart- same same, all same.

 

[snowdog61]

Electrons don't care as long as you are in contact with the part you are trying to preserve. Two anodes is overkill unless you're one of those 'hot' boats actively discharging through the shaft but then you have other issues