Bottom paint done, now electrolysis absorbing items??-gctid368757

[Guest]

Well my first time of sanding and putting bottom paint on is completed and made the boat look like new. Wow what a difference!

Now a friendly boating neighbor noticed something as he was congratulating me on the btm paint. Something about replacing the "?!&" on the lower unit That it absorbs the electrolysis that is in the water that either my boat gives off or others around do.

Anyone know what these were called or anything about them?

Thanks in advance

[RGrew176]

Impulse wrote:
Well my first time of sanding and putting bottom paint on is completed and made the boat look like new. Wow what a difference!

Now a friendly boating neighbor noticed something as he was congratulating me on the btm paint. Something about replacing the "?!&" on the lower unit That it absorbs the electrolysis that is in the water that either my boat gives off or others around do.

Anyone know what these were called or anything about them?

Thanks in advance

Probably talking about your sacrificial anodes. Perhaps they need to be replaced.

[Guest]

Yes I believe that sounds familiar to what he said. Thanks

[JimMc]

BoatZincs.com is a great site for anodes. They have some good reference charts.

There are several kinds here are general guidelines.

Zinc - Salt Water

Aluminum - Brackish water

Magnesium - Fresh Water

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Your outdrive will have several anodes. One on each trim cylinder and one or more on the drive itself.

Likely another on the hull and one on each trim tab if you have them.

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By the way do not paint the drives with bottom paint.

Leave about an 1-1/2" unpainted strip around the outdrive. This is to protect the aluminum drive from the copper in the bottom paint. See the photo below.

[Guest]

hmmm im in fresh water and i think i have zinc on mine. your saying i need mag? add that to the list for this year i guess...lol

[MidnightSun]

cbr900rr wrote:
hmmm im in fresh water and i think i have zinc on mine. your saying i need mag? add that to the list for this year i guess...lol

I am in about as fresh as fresh water gets. No need to go the pricy Magnesium route whatsoever. Have been using aluminum forever and so has everyone I know. In fact you would be hard pressed to find Mag anodes in all our local marine supply stores. If you do have zinc now, better switch them out though.

[2850Bounty]

RGrew176 wrote:
Probably talking about your sacrificial anodes.

Just an FYI, note that Rick refered to these as sacrificial anodes, of which is correct.

You'll often hear "zincs" being used as a generic term. They are only "Zincs" when the material is zinc.

Just a little pet peeve of mine!

Wayne, notice Jim's bottom paint and how it's held back from the out drives by 1" or 1-1/2" or so.

Make sure that you the did same if it's conductive bottom paint.

.

[Guest]

and the purpose of these is exactly what? And what happens if mine are gone and havent been replaced?

[Guest]

2850Bounty wrote:
Just an FYI, note that Rick refered to these as sacrificial anodes, of which is correct.

You'll often hear "zincs" being used as a generic term. They are only "Zincs" when the material is zinc.

Just a little pet peeve of mine!

Wayne, notice Jim's bottom paint and how it's held back from the out drives by 1" or 1-1/2" or so.

Make sure that you the did same if it's conductive bottom paint.

.

Crud. Umm nope. I didn't hold back on the bottom paint near the out drives. I cut it in like a painter pro. What is the purpose of holding back ?

[Guest]

Most bottom paint has metals in them.

I believe you are taking any electrical current in the water and connecting it to just the place you don't want it. You may also be getting static electricity from moving through the water. I know there are others that know more about this.

[MidnightSun]

apexaro1 wrote:
and the purpose of these is exactly what? And what happens if mine are gone and havent been replaced?

Sacrificial in that they corrode instead of the drive corroding. With them gone, your several thousand $$ drive will rot out. Not a good thing.

[Guest]

Impulse wrote:
Crud. Umm nope. I didn't hold back on the bottom paint near the out drives. I cut it in like a painter pro. What is the purpose of holding back ?

As other posters have stated, bottom paints generally contain metallic ingredients.

When two different types of metal come into contact e.g. copper in bottom paint and aluminium in your outdrive, whilst immersed in liquid (water), a process known as electrolysis can occur. Electrolysis will consequently cause corrosion of those metals i.e. your outdrive casing and inner parts may corrode.

Sacrificial anodes are used so that they can corrode instead. The materials, zinc, magnesium etc from which anodes are made tend to be the most sensitive metals to corrode during electrolysis, which is why they will "sacrifice" themselves before any metals in your outdrive will.

I hope this explains it for you.

Best to remove your bottom paint around your outdrives.

[Guest]

MidnightSun wrote:
Sacrificial in that they corrode instead of the drive corroding. With them gone, your several thousand $$ drive will rot out. Not a good thing.

Well, that would have been a good thing to know about before they splashed me... can I replave them after its in the water? I suppose i can research this on my own too, its just so easy to ask you veterans. Thanks much!

[Guest]

Yeah Wayne a must... spend the 50 bucks for the kit.. ill help ya put em on.

[JimMc]

MidnightSun wrote:
I am in about as fresh as fresh water gets. No need to go the pricy Magnesium route whatsoever. Have been using aluminum forever and so has everyone I know. In fact you would be hard pressed to find Mag anodes in all our local marine supply stores. If you do have zinc now, better switch them out though.

No arguement from me. As I said in my original post BoatZincs.com has great reference charts.

My rough guidelines was meant to be an initial offering. I always lean to the safe side offering recommendations.