anodes - extra protection???

[ozzie]

I have recently moved my boat into a south coast marina for the winter (cheaper than craning and storage!) My one concern is that the anodes on my Alpha one sterndrive wont last a year,until I lift her out in the spring for antifouling and anodes. I mentioned this to a friend who said that he had been told that for additional protection you can attach an anode to a piece of wire, hang it by the sterndrive and connect the other end to the sterndrive in the engine bay.

Two questions. Firstly does anyone have any concerns over the anodes lasting a full year, and secondly is the additional anode plausible or just an old wives tale?

 

[nordic_ranger]

It depends on the condition of the annode fitted to your boat. Only you now that. as for a second annode. It certainly not an old wives tale and is done often in Marinas.

 

[jparham]

I have them on mine because not only does it eat anodes in less than a year, it's close to a new set of props every 2 years and paint won't stay on the props.....
Situation is worse if:
a) are you going to stay connected to shore power? If yes the anode wear is worse (as you have a direct connection to the pontoon earth)
b) Is there a steel pilon close to your berth - like within 10 feet? If yes, this accelerates the galvanic effect.
So
1) Put a thick layer of prop antifoul on before it goes in
2) Connect an MGDuff pearl anode or similar via a thick piece (6mm) of earthing wire to the battery's negative terminal and hang it over the stern. I have arranged mine so that even if I do forget to haul it in before I take off, it can't hit the prop.

 

[ozzie]

Thanks!! you have answered most of my queries. I am going down to the boat this week, so I will have to get an anode. Luckily I have some 6mm earth cable and a few crimps, so can make one up. With regards to positioning, does it matter how close it is to the sterndrive or does it just have to be over the side.

 

[wp1234]

The problem I have is the rate that my small shaft anode disappears at in comparison to the larger transom mounted one. Given that I leave my boat on shore power a lot in the winter and I’m located near steel piles on a fizzing marina I too have been thinking about putting a sacrificial anode over the side to reduce the loss.
Ive considered taking a new earth band plus anode bomb over the side from the existing anode earthing wiring located in my aft locker, is this Ok to do and more importantly is it effective.
Would the forum also recommend a galvanic isolator, is it a choice of one or the other?

 

[dkm]

Do you have stainless steel props? If so you may find your anodes will not last a year regardless of what you do.
Berth well away from rusty pilons, switch of shore power when not needed and fit a galvanic isolator. If they still don't last, then Sealift at Cowes will lift you for an hour and anodes can be fitted while boat being scrubbed for less than £100.
I've heard of your suggestion but never tried it myself, interested to hear views on this

 

[Malcb]

Deleted

 

[pissativlypossed]

An extra anode will certainly help, but for complete peace of mind you should fit a galvanic isolator, an easy diy job.


Galvanic Isolator

 

[wp1234]

If you fitted a galvanic isolator does that mean you would'nt bother with an anode bomb

 

[pissativlypossed]

Nothing to stop you fitting both, the extra anode will provide additional protection and the galvanic isolator will in turn increase the life of all your anodes.

The anodes are meant to degrade over time, that is why they are known as "Sacrificial Anodes" if they don't show some sign of degradation it is most likely that they aren't doing what they are supposed to.