Heavy zinc wear early on....

[Madifonzo]

I was down the boat today doing some odds and ends. Water was dead calm for once, and I was able to see both drives. I observed the new prop anodes as very chalky looking. I raised the drives to the trailer position so I could feel the prop anodes and a lot of material flaked off. Talked to the marina and they are going to put a meter in the water and see what reads. When I asked about checking the boat out for electrical issues they suggested just a basic check as tracing issues can get very costly. They also seem to have little faith in mercathode systems claiming that they come across a lot of failed units.

By the way, boat has been in water since April 14th...how new should anodes look after less than a month?

Anyways my questions for others:
# of times people are replacing anodes in season?
any input on tracing electrical issues...worth the cost?

comments on mercathode...I have heard of people upgrading. Will the meter test tell the techs if the units are operating correctly?

Hate corrosion....

 

[src]

Several possibilities come to mind, including the Mercathode, the Galvanic Isolator and electrical leak from the docks. The Mercathode performance is degraded by current, and I've learned that in fresh water additional "pucks" might be necessary, due to the lower conductivity of the water.

I think you are on the right track having them test the Mercathode and for power leakage from the docks. Also, it could be related to a nearby boat leaking current. There are a lot of variables at play including the zinc type, quality, local water quality/conductivity, etc.

It's just an unfortunate truth that those big stainless props snugged up to the aluminum outdrives are going to drive more corrosion than we want.