Hanging Anode Over Side Re Electrolysis

[yacht surveyor]

The other thing to bear in mind is that the resistance of the wiring and the connections must be low to be effective. The connections must be good and clean. Make sure the mating surfaces are clean.

We are only talking a small voltage differential between a zinc anode and the sail drive in sea water so a substantial diameter marine grade tinned copper wire will be your best bet, to give as little resistance as possible, even if it needs replacing more frequently.

You can use a through deck electrical connection to allow you to disconnect the anode when moving if having the hatch open does not appeal in the rain!

You can get meters to measure the differential to check that the anode is being effective, but not sure where in India!

Martin

 

[Blue5]

Interesting thread, especially as I have just lifted the boat and as Seajet I have just given my cc to Volvo, new saildrive anode via Ambassador marine to accomadate the s/s rope strippper and new prop anodes that had virtually dissapeared.

My concern is that this is 12 months after I replaced them last so if dropping an anode over the side would extend the life of these items by even a few months I would be happy to try and trial it.

Now I am resonably practical but all this seems to be black magic but even on this thread there seems to be a deal of differing opinion and the more I read the darker it becomes. How do I go about finding the correct size and composition of cable, correct point of attachment to the sail drive and correct anode to use. ?????

 

[atyas]

You are quite right : cathodic protection is a well known "science" on big boats and black-magic in pleasure boats world... Probably because anodes are sacrificial instead of impressed current one. If concerned, download galvatest white paper to learn a little about the tricks (www.galvatest.com)

 

[yacht surveyor]

I would contact MGDuff directly and have a chat. They know what they are talking about and are very helpful.

Better to take the advice from people who do this day in day out.

 

[Quandary]

Interesting thread, especially as I have just lifted the boat and as Seajet I have just given my cc to Volvo, new saildrive anode via Ambassador marine to accomadate the s/s rope strippper and new prop anodes that had virtually dissapeared.

My concern is that this is 12 months after I replaced them last so if dropping an anode over the side would extend the life of these items by even a few months I would be happy to try and trial it.

Now I am resonably practical but all this seems to be black magic but even on this thread there seems to be a deal of differing opinion and the more I read the darker it becomes. How do I go about finding the correct size and composition of cable, correct point of attachment to the sail drive and correct anode to use. ?????

I use a hanging anode as detailed in my post earlier and it does seem to considerably extend the life of the very pricey modified leg anode from Ambassador but it makes absolutely no improvement to the lifespan of the anodes on the Volvo folding prop.
I tried to make a hanging anode by melting down some old zincs without success so I purchased a Plastimo from Mailspeed, (an awful lot cheaper per kg. than a Duff one) even though I clean it frequently with abrasive it is heavy enough to last for years.

 

[pvb]

.... download galvatest white paper to learn a little about the tricks

Surely the biggest trick is trying to con people into paying £25 for a bit of wire???