MerCathode or Anode

[US1Fountain]

Which item works the best to prevent galvanic corrosion? Not accounting the replacing of the anode as it wears away, but the protection either method provides.

This would be the part that is mounted to the bottom of the gimble assembly of a Mercruiser sterndrive.

Thanks

[GordMay]

The Mercathode system is an “active” impressed current system. Active systems provide a higher degree of protection than do “passive” sacrificial anodes.
I believe that Mercury recommends that the Mercathode system be installed, in addition to sacrificial aluminum or magnesium anodes, on all “Bravo” (& ‘Alpha’?) Sterndrives; hence, it shouldn’t be an either-or question.

See Mercruisers’ Manual Number 11 Corrosion Guide Part Number 90-17431—4.
➥ http://www.tsgmarine.no/deler/manual...Protection.pdf

[US1Fountain]

Thanks for the link and answer. My other boat is left kept, so never was an issue. This is all new to me.

My '95 new to me cruisert has twin Alpha drives that were corroded pretty bad and I am replacing both the drives and the transom assemblies with new, so wanting the best protection. My new transom units have the sacrificial anodes though. I will replace those with the exterior Mercathode unit and internal controller during the reinstall.

[GordMay]

Originally Posted by US1Fountain

... My new transom units have the sacrificial anodes though. I will replace those with the exterior Mercathode unit and internal controller during the reinstall.

Talk to your Merc' dealer, but I don't trhink you want to replace sacrificial anodes, but supplement them /w the Mercathode.

[US1Fountain]

No, I would just be replaceing the 1 anode on each drive to install the Mercathode system. That's the way they are all equiped today from what I gathered. Just found it odd my new transoms had the anode instead. But they are NOS units, so possibly not the standard config back when they were brand new??? Not sure.
I would still be retaining the other anodes that would require repalcement as eaten away.

Thanks again.

Jerry