Refurbishing a Zinc Anode

[newhaul]

Originally Posted by boatpoker

"Dorade"

Thanks ( dang autocorrect)

[a64pilot]

Originally Posted by savoir

No one should connect any zinc grounding wires to a shroud regardless of how good the bonding system below might be. Stainless steel is not a good conductor.

Stainless is a very poor conductor of electricity, if pure copper is the standard and is a 100 on a scale, SS is about 2.5
http://eddy-current.com/conductivity...y-resistivity/

Ideally you should connect the guppy zinc to the grounding system with copper wire.

[IdoraKeeper]

Regarding Ken's OP...this anode grinding has got to stop. Its a symptom of excessive time off. Perhaps a few months back in harness (or straight jacket) is in order. :-)

[newhaul]

Originally Posted by IdoraKeeper

Regarding Ken's OP...this anode grinding has got to stop. Its a symptom of excessive time off. Perhaps a few months back in harness (or straight jacket) is in order. :-)

You think this is bad wait for a month for the winter bailouts. Aren't you glad we live in the PNW where we can sail all year.

[sailingharry]

Originally Posted by a64pilot

Stainless is a very poor conductor of electricity, if pure copper is the standard and is a 100 on a scale, SS is about 2.5
Conductivity Of Metals Sorted By Resistivity | Eddy Current Technology

Ideally you should connect the guppy zinc to the grounding system with copper wire.

Actually, it's all about scale. Yes, copper is about 30 times as conductive, size for size, as SS. Which means a #14 copper wire (suitable for a bonding wire, I assume?), with a cross sectional area of 2mm^2, is equal in resistance per foot to a stainless bar 60mm^2 in area -- or about 9mm in diameter or 5/16" -- about the size of my standing rigging (and my chainplates are considerably thicker than that).

Of course, one of our most priced chunks of metal to protect is our prop, which is connected to the circuit by a stainless steel propeller shaft. Fortunately, it is also over 5/16" diameter.

At the electric currents involved (milli amps? micro amps?), I'm not sure the I*R drop across a short piece of stainless (by short, I mean a few feet) is measurable.

[hellosailor]

Folks probably get misled or confused, because the shrouds & stainless may be bonded and grounded as part of a lightning ground system, so they "know" stainless and the shrouds conduct to ground.

Except, what is good enough to carry a quarter million volts down to earth, isn't the same as what you need to carry one measly volt for the galvanic system. Lightning doesn't need much encouragement. It can even curl up in a plasma ball (ball lightning) and float up and down a chimney and around a room. Freaky stuff.

[Pete7]

Originally Posted by newhaul

You think this is bad wait for a month for the winter bailouts. Aren't you glad we live in the PNW where we can sail all year.

Don't forget England too, bit frosty in the mornings but a splash of brandy in the coffee helps.

I think in the med they all go home for the winter or dash for a marina in case it might rain.

Pete

[Kenomac]

Originally Posted by IdoraKeeper

Regarding Ken's OP...this anode grinding has got to stop. Its a symptom of excessive time off. Perhaps a few months back in harness (or straight jacket) is in order. :-)

Hey.... I resemble that.

[Lepke]

You can soak the zincs in Rydlyme. Works good on pencil zincs when the threads are corroded where it screws into the brass plug. Eats away the corrosion so the zinc can be changed easily.
Many years ago a ship carrying zinc and lead bars came ashore near Bodega Bay (north of Frisco). After what could be commercially salvaged it was left. Those of us that dived salvaged both metals for recasting. Whatever the zinc alloy was it worked fine. Nice commercial fishing weights, too. Wreck is still on the charts, but probably buried.

[Paul Elliott]

Originally Posted by sailingharry

At the electric currents involved (milli amps? micro amps?), I'm not sure the I*R drop across a short piece of stainless (by short, I mean a few feet) is measurable.

The few measurements I've made, and what I've read, indicate that the current might be around 10 mA. No doubt this can vary significantly depending on the boat and the situation, but the resistance of a few feet of stainless shroud won't make much of a difference. I have the gear to measure the voltage drop, but most DVM's won't have the resolution to show it. The potential difference between zinc and bronze is about 0.9V, so a few mV of drop through a stainless conductor is trivial.

Of course the shroud needs to be connected to the parts being protected via the boat's grounding network, but we already know that.

[senormechanico]

Originally Posted by Pete7

Don't forget England too, bit frosty in the mornings but a splash of brandy in the coffee helps.

I think in the med they all go home for the winter or dash for a marina in case it might rain.

Pete

Then there's this guy:

http://www.cruisersforum.com/forums/...in-191507.html

[Pete7]

Originally Posted by senormechanico

Then there's this guy:

http://www.cruisersforum.com/forums/...in-191507.html

Absolutely, we were on our way to an open air music festival. But rather than pay the outrageous entrance fee we moor up the river next to the grounds which by chance has a view of the stage. It might have been raining but we still had a BBQ that day.

[Rustic Charm]

Someone has told me today I should have zinc anodes on the ‘inside’ of my hull, down low where any water collects?

I’ve never heard of a need for this.

Do other steel boat owners do this?

I’ve just painted my engine Bay ready for a new Beta engine.

[Sailmonkey]

Originally Posted by Rustic Charm

Someone has told me today I should have zinc anodes on the ‘inside’ of my hull, down low where any water collects?



I’ve never heard of a need for this.



Do other steel boat owners do this?



I’ve just painted my engine Bay ready for a new Beta engine.

If you’ve got continuous standing water, an internal anode can’t hurt.

Ships, drilling rigs, etc.....that use seawater for ballast all have anodes inside of the ballast tanks.

[rwidman]

Originally Posted by Kenomac

How long does it last in salt water compared to zinc?

The point is not how long your anodes last, it's how well they protect the underwater metal on your boat Prop, shaft, brackets, etc.). These are expensive items and that's why we use sacrificial anodes to protect them.

Sacrificial is the key word here.