What is this mystery electrical accessory?

[MarkusK]

I have been reading threads about zinc consumption and stray current and some mention a 'guppy' zinc. This would be my assumption, but I don't like to ASSume. If it is a 'guppy' zinc, why the red wire and +ve lead?

[a64pilot]

Is that grey flat plate part of it? If so composition of flat plate?

However I’d guess some sort of radio ground plane if I’m using the term correctly, but that is just a wag

[Wotname]

Hmm...

Zincs (guppy or otherwise) don't really require such a large surface area to work adequately.

What material do you think the plate is? It doesn't look like zinc in the photo but of course, looks can be deceiving.

Maybe the person who made it had repurposed a red wire and +ve clip...

[senormechanico]

Also, zincs don't need to be shaped like a Guppy.
I suspect it's a zinc plate.

[KeelMe]

The cable and clamp looks a lot like battery charger positive lead. Odds are someone just cut that cable off of something and attached it to the plate.

That is in fact a hanging zinc or guppy sink, just not guppy shaped. The large surface area is for extended use; zincs do tend to disappear after a while. Once upon a time, if someone was going to leave their boat sitting in the marina for a long time they would use a hanging zinc like this.

[Bleemus]

Lightning ground. Clip it on the shroud and drop the plate in the water.

[KeelMe]

Originally Posted by Bleemus

Lightning ground. Clip it on the shroud and drop the plate in the water.

Now that you mention it you are probably right. The lead looks to short to go to the bonding system.

[Wotname]

^^ and a lightning ground would explain the large surface area.

For the OP, are you sure the material is zinc? From the photo, it could be a piece of slightly corroded Al plate.

What is is the cable? It looks a little small for a lightning ground, but it is a DIY device

[Bleemus]

Doesn't look like zinc to me which is why I supect it was just a DIY electrical conductor for lightning. We will never know the truth I suspect.

[RaymondR]

Paranoid alloy boat owners sometimes hand things like that over the side and clip them to a metal fitting connected to the hull to prevent electrolysis whilst in marinas.

[Stu Jackson]

Guppies all have looong red tongues, don'tcha know?

[AlanR]

If struck by lightning, it would instantly evaporate, the wire is so thin.

[Dougtiff]

In Indonesia, the lighting capital of the world, i attached a 3/8" wire cable to my upper's with a cable clamp, and when any lighting activity accured, i would throw the cable in the water, hopefully creating a direct path from the strike to the water, i never did get a hit.

[stormalong]

It is a device for measuring stray currents in the water at a marina. It is put in the water and a meter is used to determine if there is a voltage difference between the water and the marina's electrical ground.



If there are stray currents a nearby boat might be miswired or even a wiring error in the marina.


Stray currents can destroy underwater metals very quickly.

[MarkusK]

I am glad I asked and happy to see the replies.

The approx 8" x 8" metal plate is fairly light-weight, but not sure of composition. How to verify if it is zinc? Or aluminum? It is definitely not copper or steel.

I ASSume the cable is copper but will give it a scrape to be sure.

The previous-previous owner was an engineer...who knows what he was tinkering with?