Grounding Plates

[pelican]

Originally Posted by Blue_Heron

If you're going through zinks at that rate, there's probably something wrong. Water Rat's right about the bronze. If it's in the water, it's only going to make things worse.

If there are other boats moored close by, one or more of them may be introducing stray current into the water. I'm not sure how you would check that. Maybe if you put on Capt. Chuck's zinc plated undies, stick a toe in the water and lick the negative battery terminal. If it tingles there's probably stray current.

An alternative is to use an induced current system (to fix the galvanic corrosion, not to find the stray current). Merc makes one for the Bravo drives called Mercathode. It seems to have fixed the corrosion problems they were having. I don't know if it will fit an Alpha, but it probably won't. There might be a way to rig it, though.

Dave

alpha drives have the mercathode system as well...that system,it didn't "fix" anything on the early bravo III drives - that system was allready there,the repair on the BIII drives was an update on the drive itself.



dissapearing zincs:

a common cause is the trim sender - wires are broken...

another common cause is wet wiring in the boat itself...

dumb question: you're stating the cavitation zinc - what about the trim cyclinder zincs ? the zinc on the transom assembly ? these zincs burning up quickly ?

trim tabs ? zincs on them ? stainless steel prop ?

when the boat's in the water,drive tilted up - are ther any small white powdery deposits apparent on the drive ?


the true test is with a special plug in metal - on end of a DVOM is connected to the metal,it's dropped on the side in the water,the other lead on the DVOM is connected to ground - voltage is read...
not sure about the zinc coated bannana hammock ?
"electrolysis" - it's hair removal...