New Use For Sacrifical Zincs

bob

bob

New Member
May 15, 2007
110
Saco River/Coastal Waters--Maine
Boat Info
240 Sundancer 2000
Engines
5.0 Mercruiser w/Bravo III
Speaking of corrosion....

I have heard of attaching zinc "mermaids" to the dock to help deflect stray electrical currents. Being frugal, (actually cheap), I thought of putting my old zincs into a plastic onion bag (the ones that look like a net that onions are sold by at the store), and fastening it near the boat to accomplish the same thing.

Has anyone done something like this? Would the "bag" need to be grounded to my boat's ground system; if so whereor should it be grounded to the nearest shore power pylon? I had been thinking of using electrical wire to "electrically connect" all of the old zincs together. How far from the boat should it be?

Besides being economical, it would also solve the disposal problem for the old zincs.
 
Every zinc will have to be in contact with the grounding wire. Connect the gounding wire to the block which if still properly wired is grounded via the outdrive and gimbal bearning. It can be done easy enough. I' curious as to where you are going to store this box of rocks (so to speak) while underway.
 
I was told to ground it to the land electrical in your slip....???

And you just leave it hanging there when you come and go...

I am not say who is right or wrong here just what I had heard....

:huh:
 
I'm not sure that recyling used zincs will work all that well. I seem to recall that part of the argument for replacing zincs on a calender basis rather than deterioration basis was that the zinc developed a patina. this patina in turn reduced the effectiveness of the zinc.

Obviously if you are talking about old, but unused zincs then with the proper grounding they would work.

Henry
 
Hampton said:
Maybe it would be as long as you are plugged in. Makes sense.
Click to expand...

Yes, sorry I left that part out..... When you are plugged into your shore power and your old zincs dangling off your slip are connected to your ground on your shore power too.

:huh:
 
Nope good idea just won't work. The zinc is sacrificial when in a circuit between the higher nobility metals and the sea water. Thus your bronse or aluminium props, steel shafts etc do not disappear instead the zinc does. Hanging a bag of zinc junk alongside the boat but out of the circuit is sorta like winking at a pretty girl in the dark. The idea is good, but the result are aweful.

You can wire tie these chunks of zinc into a common daisy chain and hang it in the onion bag, then lead the end of the wire to your bonding system or some other Bonded metal surface and clip it on so it has good conduction and it will work for a time. But honestly ... just of buy a zinc mermaid or fish and be done with it.
 
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The Bill Collector said:
Yes, sorry I left that part out..... When you are plugged into your shore power and your old zincs dangling off your slip are connected to your ground on your shore power too.

:huh:
Click to expand...

Probably haven't got this one thought out all the way yet ... Get this little ditty, the electrical grounding system for the AC side of your boat is a totally separate and distinct circuit than your galvanic bonding system. Try this as your primary protection system and adios running gear.

Seond time, BUY A FISH!
 
Hmmm. I wasn't thinking about that. Is that acceptable? Hopefully someone who knows for sure will chime in. This is of great interest to me.

And since I don't know....Sorry guys. I guess I spoke up when I shouldn't have.


Edit.....just read Chad's posts. I feel better now.
 
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Okay why buy a zinc on a rope? All boats will have some sorta of bonding element built in. All except those home made boats built by ignorant enthusiasts.

Some boats with small zincs, under a pound or so find they are loosing zinc way to fast, maybe a pound every few weeks. They have their boat check out and are comfortable they are not mis wired, have a solid bond contact all the way through their boat and hence the loss is coming off the dock or another boat in the marina. So what to do to prevent having to constantly add more small zincs to the system. Put a really big cheap chunk'o Zinc in the water as a part of your boats galvanic system. Thus a 20# pounder with an embedded # 4 copper wire terminated in a small battery clamp is purchased and hung off the boat while attached to a bonded element of the boat. A out drive component, a stanchion you know is bonded and that 20# of zinc disappears instead of your expensive molded pretty branded zinc.

As the days and weeks pass when your boat never moves at the dock, that chunk'o Zinc is making sure your props and shafts don't leave without you too!

To get us guys to buy these globs of zinc they make them in the shape of buxom women or big fishes. Hence it feels like we have actually bought something more tangible than a chunk of metal we are going to sacrifice to Neptune.

Now don't we all feel warm and cozy inside? :smt038
 
Guess I caused some confusion when I posted this thread. I had recently read several articles on galvanic corrosion. Some of these articles talked about "stray current" found is some marinas due to improper set up of shore power, shore power cables to boats dangling in the water, etc. I've seen advertisements in nautical catelogs about these zinc "mermaids" that allegedly would attract some of these stray currents away from my boat. Even West Marine carries them.

My boat has a Bravo III zinc "kit" that has zincs for the outdrive, (ventillation plate, gimbal, hydraulic cylinders, etc.), plus my trim tabs have the zinc domes attached. It also has the Mercathode system. I usually leave my battery switch on because it's the only way power is supplied to the Mercathode system. However, I did notice a bit of bubbling under the paint near the skeg, which got my attention. The "bag o' zincs" would be IN ADDITION to the normal complement of my boat's zinc protection.

Since I've read that Bravo III outdrives are susceptible to galvanic corrosion, I just thought rather than throwing my old zincs away, they could be put to better use in ADDITIONAL protection for my boat. I was hoping to elicit a response as to how effective my idea might be. Also, should the bag o' zincs be attached to the boat or somewhere else on my slip? If you recommend attaching it to the shore power tower, where exactly should it be attached?

One of you talked about the "patina" or zinc oxide that occurs as the galvanic process occurs. Thought I might rejuvinate the old zincs with a wire brush or sandpaper.

PS: The price for zincs is outrageous. I know, you'll chime in and say it's still a lot cheaper than replacing the outdrive.
 
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I have a zinc fish that I keep in the Transom locker in a small bucket. So far it's lasted 3 years. It weighed a ton when I bought it, not so much now. When I dock the boat, I plug in my shore power and drop the fish over the side. Simple, effective. Every month I knock the dead stuff off the zinc fish, pretty much just falls off actually. If you have more time than money, I guess you could go around collecting everyone's dead zincs and wire them together and bond it to your boat, but you're probably talking a weeks worth of work for a hillbilly setup.

I read that pennies have a lot of zinc in them. you could save up a ton of pennies and wire them together and hand them off the side of your boat. I wonder if a penny half the size is still worth a penny???
 
The best use I've found for old zincs ia to melt them down and pour the molten metal in a pocket in the base of the cockpit and salon tables to make them bottom heavy and unlikely to tip over.

..........but wait, was another thread? or do I get extra points for killing 2 birds with one answer?
 
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