Anode hung overboard

[cagey]

Where should I connect an anode I plan to hang overboard this winter. My plan is old half eaten anode crimped to copper pvc sheathed wire( to prevent probs with fittings as cable comes onboard) then led below to engine earth point. Engine is bonded to shaft,prop and hull anode.
Reason for this , last year left boat in water in marina and when lifted out in March Hull anode gone, shaft anode gone but also prop buggered,£600 mistake, hope dangling anode will prevent this.
Any better ideas please.
Keith

 

[VicS]

Where should I connect an anode I plan to hang overboard this winter. My plan is old half eaten anode crimped to copper pvc sheathed wire( to prevent probs with fittings as cable comes onboard) then led below to engine earth point. Engine is bonded to shaft,prop and hull anode.
Reason for this , last year left boat in water in marina and when lifted out in March Hull anode gone, shaft anode gone but also prop buggered,£600 mistake, hope dangling anode will prevent this.
Any better ideas please.
Keith

Clipped firmly on any convenient point on the anode/engine system. Prop shaft would be good for protecting the prop specifically.

BUT With you past experiences you should be looking for a reason for the loses to be so severe.

Shorepower connected with no galvanic isolator ??
GI defective or incorrectly installed?
Some silly on board fault on the DC system.?
A fault on a nearby boat if the shorepower is connected to both?

Really sounds like electrolysis driven by a 12 volt system fault rather than just galvanic corrosion.

Testing with a Galvatest electrode or similar might be wise http://www.galvatest.com/

BTW commercial hanging electrodes are on stainless steel wire.

 

[Tranona]

Suggest you go onto the MG Duff site and look at dedicated hanging anodes and how to use them, rather than making do with old bits.

 

[maby]

Suggest you go onto the MG Duff site and look at dedicated hanging anodes and how to use them, rather than making do with old bits.

Good grief, they are expensive! £115 from Mailspeed Marine???

I would suggest doing a proper job rather than lashing something up from old scraps, but you can do a lot cheaper than that!

Get a standard pear shaped zinc anode on a steel bar - £18 from Mailspeed - and solder a reasonably thick insulated copper wire to the steel bar. It will take soft solder easily if you clean it up well and use a small gas blowtorch - don't heat the bar too much, or you'll melt the zinc off. I've always found that all I need is ordinary electrician's flux cored solder, but I guess that a bit of plumbers flux on the steel first might make the process a bit easier. Apply the solder close to one of the mounting holes drilled through the bar, tin up the copper wire, solder the two together, then tie the wire to the bar through the mounting hole so that the weight is not being taken on the soldered joint.

I've done this a couple of years running and always found it very successful. Just realised that I haven't prepared one this year - another job to add to the list.

 

[Billjratt]

I have been doing as you suggest for years and believe I extend the life of the fixed anode.
I took a wire from the stuffing box ( My engine is isolated) up to the underside of the stanchion nearest the prop and connected it to one of the fixing bolts.
When I moor up I clip the wire onto the stanchion ( I bent a "P" bracket to suit) and lower the anode over the side in line with the prop. (on the opposite side of the boat from the fixed anode, so the prop can "see" one on either side, (it's a long keeler with the prop in a smallish gap)
I use partially depleted anodes scavenged from the hard standing area.
I agree with the poster above who thinks you should investigate the cause rather than just flinging zinc at it.(or as well as....)

 

[VicS]

I took a wire from the stuffing box

There is electrical continuity between the prop shaft and the stuffing box ??
I'd expect the packing to insulate one from the other and the water trapped in the gland could cause corrosion of the shaft if there is any current flow between anode and prop

What is your hull anode bonded to ??

 

[sighmoon]

Suggest you go onto the MG Duff site and look at dedicated hanging anodes and how to use them, rather than making do with old bits.

Do you have a link?. I googled MG Duff, found the site, and then looked for a bit about hanging anodes but couldn't find it.

 

[nigel1]

Do you have a link?. I googled MG Duff, found the site, and then looked for a bit about hanging anodes but couldn't find it.

Coul'nt find it either, if you googel mg duff hanging anode you just get a pdf product list, but google hanging andoe brings up quite a bit of information.
I use a 2 kg anode on a bar with a stainless wire clamped to it, and then connected to the engine block.

 

[sighmoon]

I have a bought one. By the end of the year it was still in good condition - white but not chewed, but the (new) shaft anode has deteriorated markedly.

 

[Fantasie 19]

Do you have a link?. I googled MG Duff, found the site, and then looked for a bit about hanging anodes but couldn't find it.

Just type hanging in the search box...

 

[sighmoon]

Just type hanging in the search box...

Gives me products, but not information.

My understanding of Tranona's post was that the MG Duff site has some useful information, but re-reading it, this may not be what he meant.

 

[maby]

Gives me products, but not information.

My understanding of Tranona's post was that the MG Duff site has some useful information, but re-reading it, this may not be what he meant.

MG Duff do make a purpose built auxilliary anode, but I could not see it on their web site. Have a look at anodes on the Mailspeed Marine site - it's there, but at a ridiculous price

 

[VicS]

The hanging electrode is lumped in with zinc electrodes I think you will find.
There are a few words more about them in the commercial vessel section but only to say that they are on stainless steel wires.

I am not aware of any detailed info or advice about the use of hanging electrodes in particular on MGDuffs website ..... maybe Mr.T has found something I have not ... he is quite good at that!

 

[Tranona]

The hanging electrode is lumped in with zinc electrodes I think you will find.
There are a few words more about them in the commercial vessel section but only to say that they are on stainless steel wires.

I am not aware of any detailed info or advice about the use of hanging electrodes in particular on MGDuffs website ..... maybe Mr.T has found something I have not ... he is quite good at that!

But not very good in this case, as they seem to have changed their website since I last looked, when I recall a fair amount of explanation of the different types.

Those looking for additional protection without screwing lumps on the outside might care to look at the Ionguard thruhull anodes on the Brunton Props site. I considered fitting one of these when I was planning a trip through the French canals so that I could use an additional magnesium anode wired up to the saildrive. Trip did not happen so saved myself a lot of money - but iut would have done the job.

 

[maby]

But not very good in this case, as they seem to have changed their website since I last looked, when I recall a fair amount of explanation of the different types.

Those looking for additional protection without screwing lumps on the outside might care to look at the Ionguard thruhull anodes on the Brunton Props site. I considered fitting one of these when I was planning a trip through the French canals so that I could use an additional magnesium anode wired up to the saildrive. Trip did not happen so saved myself a lot of money - but iut would have done the job.

They do look good, don't they - but quite expensive. I was considering one, but I hate drilling holes through the hull!

 

[Tranona]

The big advantage is that you can place them close to the saildrive, whereas a hanging anode will be some distance away - plus, of course easier to wire.