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Off Topic Zinc question okay here

S

slauder

Regular Contributor
I was talking to the guy with

I was talking to the guy with his Nortic Tug at the dock next to me. He has his zinc fish hanging in back of his boat but grounded to the copper water line at the dock. Not attached to the ground wires in his boat. He said its pulling all the current away from around his boat so he is safe.

Mine is hanging near props and attached to the grounded wires that are running thru my boat. I was also thinking to attach my 1.5 inch shafts to the grounded wires with a clamp and wires. Not sure how well they contact the brass stuffing box that is grounded. I figure they have shaft zincs for a reason and my props dont have to move now for the next 8 weeks.

1. What method is better with zinc fish?

2. Should I clamp the shafts directly to the ground wires?
 
"I believe the zinc will prote

"I believe the zinc will protect whatever it is electrically connected to. If I got one "wet", the clip would be to my bonded metal.

The shaft should be connected to the block via the coupler and gear. you can measure any potential difference with a sensitive (digital) volt meter, between the shaft and the bonding system. (make sure the meter 'zeros' with the leads touching.) The exception could be the use of those 'drive saver' elastomeric coupling disks.

The stuffing boxes should be bronze, not brass. Good that they are bonded; mine aren't."
 
You want the 'guppie'

You want the 'guppie' connected to what you are trying to protect. Your neighbor is protecting the dock while his boat corrodes away!

Jeff (aluminum boat owner)
 
DUH...thats right the shafts c

DUH...thats right the shafts connect to tranny and that to engine!

So I been pretty good about replacing the ends of a few corrected green bonding wires.

What I have not done is measure the "potential difference" in different areas.

Where and how do I perform this test? I have a "sensitive (digital) volt meter".
 
"Two separate sets of tests. T

"Two separate sets of tests. The first is to measure the integrity of your bonding system. measure between the point it ties into your ground plate (or rudder plates) and the other metal components that are bonded. These should read ZERO indicating the bond is intact.

The other test is an in-the-water kind and uses a 'reference elctrode'. I think Jeff posted a link to a good corrosion website; maybe he'll repeat it. a www search on the above phrase should also show similar info. This test will show the galvanic activity in the water around the slip and can indicate the likely culprits if any anomolies are found.

hope you used a good crimper and some sealer when you put on the new terminals. Also, if the wire is "green", on the inside of the insulator, it's time has come."
 
"To determine if your anodes a

"To determine if your anodes are working properly--which means they are generating electricity instead of your boat parts corroding away--you need both a voltmeter and a galvanic probe.


In the photo I made up a test rig using a probe (70 bucks) combined with a Harbor Freight cheapo meter and some wiring. You ground one lead to the boat's grounding system and drop the probe into the water for testing. The range of voltage you are looking for is about 0.5 to 1.2 volts depending on hull materials--with my aluminum boat it's 0.09 to 1.2 volts. In MY case, since the entire hull is a conductive material, I can simply ground the lead to a railing post.

Jeff
374417.jpg
"
 
"..."Is this a Ag/AgCl ele

"..."Is this a Ag/AgCl electrode?"

Yes, but the, ah, prices have gone up a bit since I made mine!

Jeff"
 
Well this has caught my intere

Well this has caught my interest. What would be an unacceptable voltage? I assume the voltage being measured is from stray currents?

Can you point me to a good article on this subject? I have never made such a measurement.

Chuck Hanson
 
"Chuck:

The voltage you&#39

"Chuck:

The voltage you're looking for on the meter is ONLY from that being generated by your anodes. Any stray voltage will not show up on the meter since it's AC voltage--the meter reads only DC voltage.

AC voltage by itself does not cause galvanic corrosion, but it can lead to problems if it is rectified somehow into a crude form of DC voltage.

What voltage is bad for a plastic boat? Not sure (I have an aluminum boat) but anything over 0.04 volts would concern me, especially if I had outdrives.

Jeff"
 
"Thanks Jeff, this gives me a

"Thanks Jeff, this gives me a start. I Googled the subject last night. There is a ton of information but not sure if it is all on point.

Chuck"
 
"As far as the boat that has t

"As far as the boat that has the guppie in the water and connected just to the water pipe on dock...

boat is hooked up to electric via the 30 amp service. The electric is ground to water pipe I found out.

looks like he is okay then, yes?"
 
"RE: hope you used a good crim

"RE: hope you used a good crimper and some sealer when you put on the new terminals. Also, if the wire is "green", on the inside of the insulator, it's time has come.

mark,
I have been replacing obvious corrotions (or break offs). I cut inch off and look. if its green copper i cut a half inch off and look again.

crimps seem good. standard wire crimper making four notches. tool could be larger as it hurts my hand when I torque it. no sealer, but what do you use? I have some liquid tape. I'll lose inspection if I cover up..."
 
"A ratcheting crimper with the

"A ratcheting crimper with the proper sized die set is the only thing I'll use now...they are relatively cheap. For the larger sizes, I usually bite the bullet and go to the local WM, buying the ends if they use the high end crimper to place them on my wire.

Liquid tape is the only thing commonly available nowadays....Before OMC ceased to exist, they had a liquid neoprene that was far superior to 'liquid tape'. adhesive lined shrink tubes combined with liquid tape is the usual receipe for the bonding wires that I use.

On the zinc guppy to the water pipe, the short answer is NO. The pipe, if copper, is usually grounded by its installation. Same ground the AC power connection uses for the 'safety' ground. To drive the point home, if that approach worked, you could rely on your slip mate's zincs to protect your metal...know anybody doing that?"
 
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