[LODI QUACKER]

Need a little help and some info, anybody an expert???

[fat fanny]

If memory serves me correctly it is when a ferrous and non ferrous metal are in contact and a chemical reaction occurs causing a corrosion and or a material build up at the contact point. But as far as being an expert the closest your gonna get is possibly a plumber and or a metalurgist. Most of the time and most occurrences are when black pipe is mated to galvinized pipe long term effect is drainage or water flow issues due to internal sediment build up.

[freddyray21]

are you talking about the method used to clean a metal gas tank?

[Frank Acampora]

Electrolysis is the term for what happens to metal--in our case in the presence of water.

When ANY two different metals are in close proximity with each other and there is a conducting medium (fresh or salt water) then a voltage potential is set up. This is very similar to a battery, and depending upon which two metals are involved, electrons flow from one to the other. The net effect is eventual disintegration of the metal. We can preferentially USE electrolysis to protect our engine.

For a simplistic example: In salt water, the salt being a very good conductor, any metal in the area of the boat will set up the galvanic reaction and since aluminum is usually more active than dock metal or anchor chain, or even the dissolved metals in the water, it will be sacrificed first. NOW: Since pure zinc is much more active electrically than aluminum, if we solidly attach a piece of zinc to the engine below the water, it will corrode first, protecting the aluminum. ---MAYBE! Nothing is foolproof.

There are electrical systems that "impress" a reverse current over the galvanic battery and purport to stop electrolysis. I don't know; I have no experience with these systems, but the logic is sound.

[steelespike]

To add even more fun a boat in a marina can suffer damage from neighboring boats with a problem or even the marina setup.

[HappierWet]

Electrolysis is the passage of an electric current through an ionic substance that is either molten or dissolved in a suitable solvent, resulting in chemical reactions at the electrodes and separation of materials.


Galvanic corrosion is an electrochemical process in which one metal corrodes preferentially when in electrical contact with a different type of metal and both metals are immersed in an electrolyte.

Hate to be a stick in the mud....BUT....one is the process of two dissimilar metal IE. a sacrificial zinc, the other is the result of passing a current thru a metal ( in certain circumstances ) like an aluminum hull used as an electrical ground.

Hope this helps.

[Cofe]

Here is an article that I researched out awhile back, hope this helps you.

Electrolysis is much more destructive to boats than galvanic corrosion. You can reduce electrolysis with these iteas:
· Avoid the use of common automotive battery chargers on your boat. These chargers use an autotransformer in which the primary and secondary windings are electrically connected. Marine battery chargers use an isolation transformer. An isolation transformer has separate windings and does not allow current to pass into the vessel from the utility connection
· Vessels using a positive ground electrical system should avoid mooring next to one with a negative ground system
· Check the connections to any two bilge pumps that are electrically connected. Ensure that each pump shares the same positive and ground connection. If one pump is grounded to the frame and the second is not, a stray current will be introduced
· Electric welders can introduce current into salt water due to frayed or damaged connectors. If welding is required on a vessel, it is better if the welder is mounted on the boat being welded
· Check your vessel for reversed polarity
· Check to see if any severe corrosion is present near telephone connections. Telephone service voltage can introduce 48 volts of current into the water
· Install sacrificial zincs on your boat and properly maintain them
· Keep a layer of quality bottom paint applied to all hull surfaces in contact with the water
· Tilting your outboard motor out of the water may completely eliminate corrosion
One ideal solution for vessel owners is to purchase and install an isolation transformer for their vessel electrical system. Vessels moored along each other act like the plates within a battery. One boat can introduce current into the water and damage may not occur until it reaches a boat six spaces down. Using an isolation transfer effectively takes you out of the battery and protects the boat from introduced stray current.
Marinas should have a policy in place to address the proper use of shore power cords. Shore power cords need to be designed for use in the marine environment and UL approved. Don't use a common household extension cord for your boat! Marine power plugs and receptacles are built to standards set by the National Fire Protection Association. Using the wrong plug in the wrong receptacle or use of a worn fixture can cause fire and corrosion problems.

[Home Cookin']

I read about a marina having lots of problems; turns out the underwater power cable was "leaking" and caused lots of damage to the boats moored nearby.
I accidently left my key "on" overnight Saturday, moored in salt water, and Sunday when I pulled the boat out noticed lots of what appeared to be salt crystals on the motor parts where they dipped into the water, especially where paint had rubbed off (22 year old motor). Low battery, too.

[LODI QUACKER]

OK, learned a llitte, ok a lot.

Now I do suppose it is a bad idea to gound directly to your AL boat?

Are there different electrodes? Are different ones supplied from the Manufacturer?



How do you know what is on your motor if there are different ones?


Do they go bad or just disssapear?


When should you change them?

Where do you get exactly what you need??


Thanks guys.