Electrolysis question

[Go Harley]

I posted this in the main forum then realized that maybe you Dogs might be better suited to answer this.

I've got a 17½' Alumaweld Stryker with a Merc 65 Jet. I've used it in the salt a few times, then dipped it in a freshwater lake to flush the salt out.

What I've got happening is little pits in the hull that I'm sure is caused by electrolysis. I've disconnected all the ground wires from the battery and then reconnected them one by one checking for a ground between the hull and positive post. I found that the main ground wire going to the Merc is grounding to the hull. Is it possible to isolate the motor ground from the hull? What kind of options do I have?

Also, how can I add more zinc? I've only got one piece affixed to the lower unit. I saw in another thread about welding directly to the hull. Is that the most recommended? Is there a formula, or rule of thumb, for the amount of zinc one should have?

Thanks.

[Skipper]

I have an alum boat also. I went to West Marine to buy zinc, but the salesman said why introduce another hot spot on the boat? He said as long as you don't moor it in saltwater, and hose it off each time, then you don't need additional zinc.

I try to hose it off within a few hours after removing it from the salt. Now after 3 years of use, My Harbercraft hull is OK. The only zinc is the outboard skag.

Cheerio'
Skipper

[corkyking]

This might help. :smile:

[fish assassin]

As you may or may not know, I have had some severe electrolysis problems while
moored at Depoe Bay (earlier threads describe the issues/causes). A boat buck
later ($1000) I have the problem pretty much solved ...

My aluminum flow-thru fish boxes were starting to show some areas of pitting due
to the Nasty "E". I took a couple of chunks of zinc that I bought at Englund
Marine and just threw them in the boxes. As long as the zinc makes contact with
bare metal they will work.

Problem solved. No more problems in the fish boxes!! I also dropped a couple
of chunks of zinc down in my bilges in the engine compartments. There always seems
to be a little salt water in there and I figured better safe than sorry!

-assAssin-